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DEPARTMENT OF AGRICULTURE: 

BUREAU OF PLANT INDUSTRY— BULLETIN NO. 85. 









u. 'j 



THE PRINCIPLES OF MUSHROOM GROWING 
AND MUSHROOM SPAWN MAKING. 



B. M. PUGGAR. 

Professor op Botany in the University of Missouri, and 

Collaborator of the Bureau of Plant Indi stkv. 



VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL 
INVESTIGATIONS. 



Issued Novembeb 15, 1905. 




WASHINGTON: 

government i-rinting office. 

L 90 5 . 




Book • 3>8{ 



/i 



'3i 






Bui. 85, Bureau of Plant Industry, U, S Dept. of Agriculture. 



Plate I. 




U. S. DEPARTMENT OF AGRICULTURE. 

BUREAU OF PLANT INDUSTRY— BULLETIN NO. 85. 

B. T. GALLOWAY, Octtf of Bureau. 



THE PRINCIPLES OF MUSHROOM GROWING 
AND MUSHROOM SPAWN MAKING. 



B. M. DUGGAR, 

I' 
Professor of Botany in the University of Missouri, and 

Collaborator of the Bureau of Plant Industry. 



VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL 
INVESTIGATIONS. 



Issued November 15, 1905. 




WASHINGTON: 
government printing office. 

19 5. 









BUREAU OF PLANT INDUSTRY. 

B. T. GALLOWAY, 

Pathologist and Physiologist, and Chief of Bureau. 

VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL INVESTIGATIONS. 

Albert F. Woods, Pathologist and Physiologist in Charge, Acting Chief of Bureau in 

Absence of Chief. 

BOTANICAL INVESTIGATIONS. 

Frederick V. CoviLLE, Botanist in Charge. 

FARM MANAGEMENT. 

W. J. Spillman, Agriculturist in Charge. 

POMOLOGICAL INVESTIGATIONS. 
G. B. Braokett, Pomologist in Charge. 

SEED AND PLANT INTRODUCTION AND DISTRIBUTION. 

A. J. Pieters, Botanist in Charge. 

ARLINGTON EXPERIMENTAL FARM. 

L. C. Corbett, Horticulturist in Charge. 

INVESTIGATIONS IN THE AGRICULTURAL ECONOMY OF TROPICAL AND SUB- 
TROPICAL PLANTS. 

O. F. Cook, Bionomist in Charge. 

DRUG AND POISONOUS PLANT INVESTIGATIONS AND TEA CULTURE 
INVESTIGATIONS. 

Rodney II. True, Physiologist in Charge. 

WESTERN AGRICULTURAL EXTENSION. 

Carl S. Scofield, Agriculturist in Charge. 

EXPERIMENTAL GARDENS AND GROUNDS. 
E. M. Byrnes, Superintendent. 
SEED LABORATORY. 

Edgar Brown, Botanist in Charge. 



J. E. Rockwell, Editor. 
James E. Jones, Chief clerk. 



VEGETABLE PATHOLOGICAL AND PHYSIOLOGICAL INVESTIGATIONS. 

SCIENTIFIC STAFF. 

Albert F. Woods, Pathologist ami Physiologist in Charge. 

Erwin F. Smith, Pathologist in Charge of Laboratory of Plant Pathology. 

Herbert J. Webber, Physiologist in Charge of Laboratory of Plant Breeding. 

Walter T. Swingle. Physiologist in Charge of Laboratory of Plant Life History. 

Newton B. Pierce, Pathologist in Charge of Pacific Coast Laboratory. 

M. B. Waite, Pathologist in charge of Investigations of Diseases of Orchard Fruits. 

Mark Alfred Carleton, Cerealisi in Charge of Cereal Laboratory. 

Hermann von Schrenk. in Charge of Mississippi Valley Laboratory. 

P. H. Rolfs. Pathologist in Charge of Subtropical Laboratory. 

C. O. Townsend, Pathologist in Charge of Sugar Beet Investigations. 

T. H. Kearney, A. D. Shamel, Physiologist*. Plant Breeding. 

P. II. Dorsett." Cornelius L. Shear, William A. Orton, W. M. Scott, Ernst A. 

Bessey. E. M. Freeman, Pathologists. 
E. C. Chilcott, Expert in Cultivating Methods. Cereal Laboratory. 
C. R. Ball, Assistant Agrostologisl . Cereal Loboraloru. 
Joseph B. Chamberlain/ J. Arthur Le Clerc.c Physiological Chemists. 
Flora W. Patterson, Mycologist. 
Charles P. Hartley, Karl F. Kellerman, Jesse B. Norton, Charles J. Brand, 

T. Ralph Robinson, Assistants in Physiology. 
Deane B. Swingle, George G. Hedgcock, Assistants in Pathology. 

I'ERLEY SPAULDING. P. .1. O'GARA, FLORENCE HEDGES, HENRY A. MILLER. ERNEST B. 

Brown, Leslie A. Fitz, Leonard L. Harter, John O. Merwin, A. H. Leidigh, H. F. 

Blanchard, Scientific Assistants. 
W. W. Cobey, Tobacco Expert. 
John van Leenhoff, Jr., T. D. Beckwitii. Experts. 

" Detailed to Seed and Plant Introduction and Distribution. 
'' Detailed to Bureau of Chemistry. 
' Detailed from Bureau of Chemistry. 



WAP. 31 19C3 
D. ot D. 



LETTER OF TRANSMITTAL. 



U. S. Department or Agriculture, 

Bureau of Plant Industry, 

Office of the Chief, 
Washington, I>. <"., August 81, 1905. 
Sir: I have the honor to transmit herewith a paper entitled " The 
Principles of Mushroom Growing and Mushroom Spawn Making," 
and to recommend that it be published as Bulletin No. 85 of the series 
of this Bureau. 

This paper was prepared by Dr. B. M. Duggar, Professor of 
Botany in the University of Missouri and Collaborator with the 
Office of Vegetable Pathological and Physiological Investigations of 
this Bureau. Under the direction of the Pathologist and Physiolo- 
gist, Doctor Duggar has been engaged for several years in the inves- 
tigation of mushroom culture in all of its phases, and great advances 
have been made, especially in the production of purer and better 
spawns. 

The accompanying illustrations are necessary to a complete under- 
standing of the text of this bulletin. 

Kespectfully, B. T. Galloway, 

Chief of Bureau. 
Hon. James Wilson, 

Secretary of Agriculture. 

3 



PREFACE. 



The bulletin submitted herewith presents the results of the work 
up to the present time on the problems of mushroom culture and 
spawn making. The first publication on the subject from the stand- 
point of pure culture was Bulletin No. lfi of the Bureau of Plant 
Industry. This was followed by a Farmers' Bulletin (No. 204) on 
mushroom culture, presenting the results of our work for the use of 
the practical grower. As an outcome of the work Doctor Duggar 
has already accomplished, spawn of pure-culture origin is now being 
produced on a very large scale by several growers and is giving excel- 
lent results. This method enables the grower to improve and main- 
tain the most desirable varieties of mushrooms in the same manner as 
is possible with other plants propagated from cuttings or buds. 
Information which would enable a grower to accomplish this has not 
been up to this time available. The general method of securing pure 
cultures as here described will enable the experimenter to cultivate 
spawn of other edible species of mushrooms in case it should be found 
desirable to cultivate them. The methods described differ radically 
from any hitherto used. They are of more general application and 
give far better results. 

For the past three years this work has been carried on in coopera- 
tion with the University of Missouri, Doctor Duggar having left the 
Department to accept the professorship of botany in that institution. 
We wish to express our appreciation of the facilities furnished by 
the university for continuing this work. 

Albert F. Woods, 
Pathologist nn<1 PJujsiologist. 

Office of Vegetable Pathological 
and Physiological Investigations, 

Washington, D. C, June 16, 1905. 

5 



CONTENTS. 



Page. 

Introduction. 9 

General considerations 10 

Market conditions 11 

Germination studies 12 

Review of earlier work . . 12 

Experimental work 14 

Tissue cultures __ 18 

Nutrition 23 

Growth on manure and other complex media 23 

Growth on chemically known media 26 

Tabulation of special results 26 

Acid and alkaline media . 30 

Temperature and moisture ... 31 

Preparation of the compost _ ... 33 

Installation of beds 37 

Spawning and casing the beds _ 38 

Mushroom growing . . 39 

Experiments at Columbia, Mo 39 

Variability in mushrooms grown under different conditions 45 

The cultivation of various species of mushrooms. . 46 

Cooperative experiments . 47 

Cave facilities in the United States 48 

Open-air culture 49 

Mushroom spawn making . 52 

A " chance " method 52 

A " selective " method 53 

Pure-culture precautions. 53 

The tissue-culture method 54 

The commercial process 55 

The vitality of mushroom spawn _ .... 58 



ILLUSTRATIONS. 



Page. 
Plate I. A fine bed of mushrooms grown from spawn of pure-culture 

origin Frontispiece 

II. Fig. 1. — A fine cluster of Agaricus campestris, the horticultural 
variety Columbia. Fig. 2. — Morels (Morchella eseulenta), one 
of the finest edible fungi - - - 60 

III. Fig. 1.— Agarieus fabaceus, the almond-flavored mushroom. Fig. 

2. — Agaricus villaticus, a promising species, fleshy and prolific. 60 

IV. Fig. 1. — A young specimen of the common puffball (Calvatia 

crauiiformis). Fig. 2. — The oyster mushroom (Pleurotus os- 

treatus) , growing on decayed willow log - 60 

V. Fig. 1. — A mushroom house provided with gas-piping framework 

for shelf beds. Fig. 2. — The preparation of compost i 60 

VI. Fig. 1. — A large mushroom establishment — a common form of 
mushroom house. Fig. 2.— The method of making pure cul- 
tures, showing the apparatus and materials 60 

VII. Fig. 1.— Mushrooms prepared for the American market. Fig. 

2. — Good ( ' ' well-run ' ' ) mushroom spawn, brick form 60 

8 



B. P. I. — 182. V. P. P. I. — 142. 

THE PRINCIPLES OF MUSHROOM GROWING AND 
MUSHROOM SPAWN MAKING 



INTRODUCTION. 

For a number of years there has been an increasing demand in the 
United States for information concerning mushroom growing. In 
the horticultural and agricultural press many individual practices 
have been presented ; but in order to give rational encouragement to 
mushroom growing in favorable sections of this country it was recog- 
nized at the outset of the investigations undertaken by the writer that 
much experimental work would be required. Bearing upon the cul- 
ture of Ag amicus campestris " a number of physiological questions 
were demanding attention, for it was desirable to ascertain (1) the 
conditions of spore germination, in order that " virgin " spawn might 
be propagated and the principle of selection attempted; (2) the 
relation of this fungus to nutrients, or a determination of the sub- 
stances or compounds which might best serve as food materials; and 
(3) the relation of the growing mycelium and of mushroom produc- 
tion to temperature, moisture, and other conditions of the environ- 
ment. In the next place it would be necessary to determine the 
application of any physiological principles established to the practice 
of mushroom growing and mushroom spawn making. 

In connection with a presentation of the results of the experimental 
work b it seems desirable to include also a more or less comprehensive 
account of the present status of mushroom growing at home and 
abroad. 

o Throughout this paper the writer has employed the generic name Agaricus 
in the sense in which it is usually understood by those interested in the practical 
side of the work. 

<> During 1903-4 the writer was assisted in the experimental work by Mr. A. 
M. Ferguson, instructor in botany in the University of Texas, at that time special 
agent of the Department of Agriculture, and during 1004-fi similar assistance 
has been rendered by Mr. L. F. Cbilders, student assistant. Through the assist- 
ance thus given it has been possible to complete an unusual amount of 
experimental work, only a portion of which can be described in detail, although 
it has all been taken into consideration in the conclusions drawn. 

9 



10 MUSHROOM GROWING AND SPAWN MAKING. 

It is not possible at this time to give more than a few brief sugges- 
tions concerning the possibility of cultivating other edible species 
than Agaricus campestris. The determination of the fundamental 
needs of diverse species will require study during a term of years. 

GENERAL CONSIDERATIONS. 

The propagation of Agaricus campestris does not seem to have been 
undertaken to any extent by the ancient Greeks or Romans. The 
occasional references to mushrooms in the classics are very general, 
as a rule, and do not suggest that artificial propagation was attempted. 
In the vicinity of Paris Agaricus campestris has been cultivated for 
several centuries, and the plants have certainly been sold on the open 
market quite as long." It has not been jjossible to ascertain whether 
the methods now in vogue are essentially the same as those employed 
a few centuries ago. It is very probable, how T ever, that the methods 
have been gradually improved. It would appear that the cultivation 
in caves is comparatively recent. The earliest records obtainable 
concerning the cultivation of mushrooms in the underground quarries 
indicate that this practice was not common previous to the nineteenth 
century. 

Mushrooms are to-day extensively grown in England and France, 
and to a limited extent in Belgium, in Germany, and in many other 
countries. Paris remains, however, the center of commercial pro- 
duction. In the vicinity of that city the culture of mushrooms is now 
almost entirely confined to the underground limestone quarries or 
cement mines. The caves used for this purpose are termed " carrieres " 
or " champignonieres." These caves may consist of a labyrinth of gal- 
leries, or halls, ranging from 5 to 50 feet in width and from 5 to 30 
feet in height. In some regions the earth is practically honey- 
combed by them, and the extent of the cave space used by the larger 
growers may be measured by miles. For the most part the ventila- 
ting system is perfect, every cave system possessing numerous air 
shafts, protected at the surface by wooden towers. Artificial parti- 
tions in the caves themselves enable the operator to control the venti- 
lation. Until recent times the cultural methods have been more or 
less sacredly guarded by the growers, and even to-day it is not easy 
to get permission to make a casual visit to the champignonieres. In 
many cases the work has been followed from generation to generation 
within the same family. There are at present, however, large corpo- 
rations in control of some of the most famous caves. 

o In a painting of the early seventeenth century (that of a Fishmonger's and 
Poulterer's Shop, by Jordaens and Van Utrecht, in the Gallery of Old Pictures. 
Brussels) Agaricus campestris and Boletus are shown on sale as a conspicuous 
part of a market scene. 



MARKET CONDITIONS. 11 

In the United States fresh mushrooms have only recently been of 
any importance commercially, although florists and gardeners of 
English and French training have long been successful growers on 
a small scale. Nevertheless, during the past decade or so, the record 
of failures has been most conspicuous, and it is certain that of the 
many who attempted this work only a few, relatively, were uniformly 
successful. 

The conditions under which mushrooms may be successfully grown 
are limited, and intelligent attention is therefore essential. It must 
be said, moreover, that the majority of failures may be directly 
traced to erroneous ideas as to the cultural requisites, or to a reckless 
disregard of conditions. The essential conditions will be subse- 
quently defined in detail, but it may be stated here that failures are 
usually due to one or more of the following causes: (1) Poor spawn; 
(2) very poor manure; (3) unfavorable temperature; and (1) heavy 
watering during the early stages of growth. 

Under suitable conditions mushrooms may be grown with assur- 
ance of success. Ordinarily they are grown only where the condi- 
tions may be controlled, and success should therefore be invariable. 

MARKET CONDITIONS. 

In the vicinity of Paris the mushroom industry has been remark- 
ably developed during the past eight or ten years. The total product 
sold through the central market of Paris in 1898 was nearly 4,000,000 
pounds; the quantity for 1900 is given as approximately 8,500,000 
pounds, and for 1901 nearly 10,000,000 pounds. These figures show 
most convincingly the present status of the mushroom industry in 
France. It may be safely assumed that more than one-third of this 
quantity is consumed in a fresh state in and about the city. The 
growth of the canning industry during this period has also been 
remarkable. In 1898 about 1,800,000 pounds were preserved, while in 
1901 the canned product amounted to nearly f>,200,000 pounds. Dur- 
ing 1901 the approximate monthly production of mushrooms ranged 
from 651,000 pounds to 985,000 pounds, from which it is evident that 
these caves yield heavily throughout the year. In some instances 
growers are able to get a crop every four or five months. 

It is extremely difficult to estimate the quantity of mushrooms 
grown in the United States. It is certain, however, that the produc- 
tion has increased very greatly, and particularly within the last four 
or five years. In the vicinity of several of our larger cities there are 
to-day individual growers who produce more than the total commer- 
cial output in the neighborhood of those cities ten years ago. 

There is now a very good open market for fresh mushrooms in a 
few of the larger cities, although many large growers continue to 



12 MUSHROOM GROWING AND SPAWN MAKING. 

sell entirely by contract or by special orders to hotels and restaurants. 
With such an enormous comparative consumption of the canned 
product, there is every reason to believe that fresh mushrooms can 
be, sold in much greater quantity as soon as this product becomes a 
certain factor in the market. With canning factories to take the 
surplus product, growers could afford to accept a smaller margin of 
profit, and this would place mushrooms within reach of many who 
may not be able to purchase them at present average prices. Agaricua 
campestris and its varieties and allied species are perhaps the only 
fresh mushrooms commonly salable in the markets of American 
cities. Throughout practically the whole of Europe several other 
species are legitimate, market products. The more delicate or fleshy 
forms of the latter are sold as fresh mushrooms; others are dried, 
and some of these, being tougher, are used only for soups, sauces, and 
gravies. Besides the various species of truffle and morel, any special 
mention of which will be omitted here, the French market to-day 
legalizes the sale of five or six other species of mushrooms. 

GERMINATION STUDIES. 

Review of earlier work. — In a small way the germination of the 
spores of Basidiomycetes has received attention from the earliest 
times. A complete historical review of the literature dealing with 
spore germination will be found in Bulletin No. 16 of the Bureau of 
Plant Industry. It will be seen that most of the early work fur- 
nishes only incidental references to spore germination. By far the 
most important contributions made by early workers to this particu- 
lar subject were several papers by Hoffmann. It is not to be expected 
that the method employed by him would yield accurate results. 
Nevertheless, the work of Hoffmann is comprehensive for that time. 
Brefeld,'' in his extensive reports upon the Basidiomycetes, gives the 
results of germination studies with a large number of the fleshy fungi. 
More than 200 species were used in his various experiments, and suc- 
cessful germination is recorded for about 1G0 species. 

In 1898 the writer became interested in some attempts to germinate 
the spores of certain Basidiomycetes. Subsequently the problem 
received incidental attention in connection with some general studies 
on the physiology of spore germination.'" The work progressed only 

a Hoffmann, H. Ueber Pilzkeimungen. Botan. Zeitg., 10:200-214, 217-210. 
1859. Beitriige zur Entwickelungsgeschiebte und Anatomic tier Agaricineen. 
Botan. Zeitg., 18:380-395, 397^104. I860. Uutersuchungen iiber die Keimung 
der Pilzsporen. Jahrb. f. wiss. Botanik, 2 : 267-337. 1860. 

t> Brefeld. O. Botanisehe Untersuchungen iiber Schimmelpilze. Basidiorny- 
ceten, I, Bd. I. II. 3. 1877. Untersuch. a. d. Gesammtgebiete der Mykologie. 
Basidiomyceten. II. II. 7: III. II. 8. 1888-89. 

cDuggar, B. M. Physiological Studies with Reference to the Germination of 
Certain Fungous Spores. Bot. Gaz., 31 : 38-66. 



GERMINATION STUDIES. 13 

far enough to suggest that an investigation of the factors influencing 
germination might yield studies of special interest. During 1900- 
1901 Dr. Margaret C. Ferguson undertook a systematic investiga- 
tion of the relation of stimuli to germination in certain species. 
The results" have made it evident that the problems involved are 
not the well-known simple nutrient or physical factors. Miss Fer- 
guson spent much time in experimenting with a great variety of 
nutrient media and special stimuli. Several thousand cultures were 
made. In the majority of these cultures Agaricus campesto*i& was 
used, and it is shown that from the known ecological relationships 
of this fungus one could not possibly predicate the probable stimulus 
for germination. In fact, with no known nutrient medium or special 
chemical stimulus employed, was there anything more than erratic 
germination. Nevertheless, the work was finally very successful 
in the discovery that almost a perfect percentage of germination 
could be secured by the influence of the living hyphse of Agaricus 
campestris upon the spores, as announced in the statement that " if 
a few spores are able to germinate under the cultural conditions, 
or if a bit of the mycelium of Agaricus campestris be introduced into 
the culture, the growth resulting will in either case cause or make 
possible the germination of nearly all the spores of the culture, pro- 
vided, of course, that the other conditions are not such as to inhibit 
germination." 

The stimulus would seem to be of enzymatic nature. No other 
mycelium tested produced a similar effect. This was a distinct 
advance in our knowledge of factors influencing germination. The 
stimulus, however, could only be looked upon as perhaps a substitu- 
tion stimulus. It did not seem possible that it could obtain in nature, 
nor could it be looked upon as wholly satisfactory from a practical 
point of view. 

Miss Ferguson's results offered encouragement ; but, nevertheless, 
the problems with Agaricus campestris and related species were left 
open for further investigation. It should, perhaps, be emphasized 
that prior to 1002 no method had been published, so far as can be 
learned, whereby one might be able to obtain with uniformity the 
germination of Agaricus campestris. It is quite certain that Chev- 
reul and others obtained at best only erratic results. Nevertheless, 
as early as 1893 Costantin and Matruchot b announced that a method 
had been developed by them whereby they were able to germinate the 

a Ferguson, M. C. A Preliminary Study of the Germination of the Spores of 
Agaricus Campestris and Other Basidiomycetous Fungi. Bulletin No. 1G. Bu- 
reau of Plant Industry, U. S. Dept. Agriculture, pp. 1-43. 1902. 

6 Costantin and Matruchot. Nouveau procede de culture du champignon de 
couche. Compt. Rend, de l'Acad. des Sci., 117 (2) : 70-72. (Compare, also, 
Bui. Soc. de Biol., 2 December, 1893.) 



14 MUSHROOM GROWING AND SPAWN MAKING. 

spores and to grow in pure culture the mycelium of Agaricus eam- 
pestris. Information concerning the details of the method employed 
was avoided in the reports of this announcement and in subsequent 
references to the process." In the first announcement the method is 
stated as follows: 

Method followed. — The spores are collected free from contaminations, and 
in order to preserve them in that condition are sown on a certain sterilized 
nutritive medium. We obtain in this manner a twisted mycelium which con- 
stitutes pure spawn. By repeated cultures ou an identical substratum the 
spawn can he multiplied indefinitely, and is transferred at a proper time to 
sterilized manure, where it develops abundantly in several weeks. At that 
stage it possesses the characteristic appearance and odor of natural spawn. 
It can then be sown in a bed of ordinary manure, to which it adheres and where 
it grows and fruits normally. 

In the later paper cited, writing of the recent improvements in 
mushroom culture, Costantin expresses himself as follows : 

We have succeeded in manufacturing an artificial spawn obtained from the 
spore germinated on a medium free from contamination. It is then pure 
spawn. We can state further that it is virgin spawn. 

In 1897 Repin h claimed to have independently arrived at results 
similar to those obtained by Costantin and Matruchot, Concerning 
his germination studies he says : 

It is only recently that the study of this question has been renewed, inde- 
pendently and simultaneously by Costantin and Matruchot. 

There is nothing unusual in the germination of the spores of Agaricus. 
Spores can be germinated on media such as used in bacteriology, on wet sand, 
or in moist air as well as on manure. Without doubt, germination is not pro- 
duced with tile same spontaneity and rapidity as in the case of the spores of 
lower fungi, which fact makes it necessary to promote the process by some 
artifices, but they are only sleight-of-hand tricks, variable according to the 
operators, and which are acquired after some unsuccessful attempts. The 
spores which should germinate (and these are always in the minority) begin 
by swelling. This very simple method makes it possible to obtain virgin 
spawn at pleasure. It is applied industrially in the manufacture of spawn of 
Agaricus from cultures which I have made. 

So far as the writer has been able to ascertain, therefore, no descrip- 
tion of the method employed by the above writers is to be found. The 
report of Miss Ferguson's work is accordingly the only available 
scientific record defining the conditions under which germination 
had been constantly obtained up to this time. 

Experimental work. — The writer has been able to confirm Miss Fer- 
guson's work repeatedly, and at the same time numerous series of 
experiments have been made to test further the possibility of influenc- 

" Constantin, J. La culture du champignon de couche et ses recent perfection- 
nements. Extrait du Revue Scientifique. April, 1S94. 

6 Repin. C. Le blanc vierge de semis pour la culture du champignon de 
couche. Revue Generate des Sciences. (September 15, 1S97. ) 



GEKMINATION STUDIES. 



15 



ing germination by chemical stimuli. In distilled water, on the one 
hand, and in plant decoctions (such as decoctions of beans, sugar 
beets, mushrooms, potatoes, etc.) and in bouillon, on the other hand, 
there have been tested a large number of inorganic and organic salts, 
carbohydrates, nitrogenous compounds, and active enzymes. 

The results of one series of experiments are tabulated in detail. 
In general, it has been found that dulcite, monobasic magnesium 
phosphate, magnesium phosphite, magnesium potassium ammonium 
phosphate, ammonium molybdate, magnesium lactophosphate, dibasic 
calcium phosphate, and other salts, especially phosphates, have in one 
medium or another been more or less effective as stimuli for germina- 
tion. Unfortunately, none of the substances mentioned, apparently, 
are very strong stimuli ; they are unable to cause invariable germina- 
tion in all nutrient media. Moreover, in subsequent series, where the 
conditions have been the same, within experimental possibilities, 
wholly analogous results have not always been obtained. No account 
has been taken, however, of the particular variety of Agancus cam- 
pestris from which the spores were obtained, and it may be that this 
will influence the results. 

It is to be noted from the following table that Miss Ferguson's 
method of employing living bits of mycelium was modified by the use 
of small pieces of the inner tissue of a young mushroom taken under 
sterile conditions. It was found that often a new growth of mycelium 
was developed from this tissue. Whenever this growth appeared, 
the influence upon spores in the drop culture was, as might be 
expected, the same as had been demonstrated for the living mycelium. 
Frequently a few spores germinated within from three to five days. 
The most interesting conclusion, however, which could be drawn from 
the cultures in which small bits of tissue were used was the following: 
Under favorable conditions a small piece of the inner growing tissue 
of a mushroom is capable of producing a mycelium with great readi- 
ness. This fact has been utilized, as shown in detail later, in the 
development of a new and effective method of securing pure cultures 
of flesh}' fungi in general. 

Table I. — Extent of germination. 



No. 


Media. 


After 3 days. 


After 5 days. 








1 

2 
3 
















i per cent KH»P0 4 


do. 


Do. 


4 




do 


Do. 


5 


i per cent K-HPO,.. 


do 


Do. 


6 




do... 


Do. 


7 


i per cent Na»HP6 4 


do... 


Do. 


8 




do.. 


Do. 


9 


} percent (NH 4 )oHPO, 


do 


Do. 


10 


i per cent (NH^HPOi in bou- 


do 


Do. 









6329— No. 85—05 M- 



16 



MUSHROOM GROWING AND SPAWN MAKING. 
Table I. — Extent of germination — Continued. 



No. 



Media. 



After 3 days 



After 5 days. 



in 



43 



} per cent MgH 4 fP0 4 ) 2 

\ per cent MgH 4 (P0 4 )<• with bou- 
illon. 

\ per cent MgHP0 4 - 

i per cent MgHP0 4 in bouillon _ _ 

I per cent MgtNH 4 >P0 4 . 

I per cent Mg(NH 4 )P0 4 in bou- 
illon. 

i per cent MgKtNH 4 )P0 4 

ipercentMgK(NH 4 )H 2 (P0 4 )oin 
bouillon. 

* per cent (NH^CAOfi 

I per cent <NH 4 wC 4 H 4 ( -, in bou- 
illon. 

i per cent magnesium lactophos- 
phate. 

£ per cent magnesium lactophos- 
phate in bouillon. 

1 percent CajHo(P0 4 ) 2 

I per cent Ca ,H-i P0 4 )■> in bouillon 

i per cent KCHOo 

i per cent MgHPO t ..- 

i per cent MgHPO- { in bouillou__ 

I per cent MgK(NH 4 )H 2 (P0 4 ) L . 
in mushroom decoction. 

i percent KH 2 P0 4 in mushroom 
decoction. 

j per cent K 2 HP0 4 in mushroom 
decoction. 

I per cent NaoHP0 4 in mush- 
room decoction. 

i percent (NH 4 ) 2 HP0 4 in mush- 
room decoction. 

£ per cent MgHP0 4 in mush- 
room decoction. 

do 

^pi.*rcentMg(NH 4 )P0 4 in mush- 
room decoction. 

i per cent ( NH 4 i 3 C 4 H 4 0,-, in mush- 
room decoction. 

i per cent magnesium lactophos- 
phate in mushroom decoction. 

I per cent CaoHjtPCV^ in mush- 
room decoction. 

| per cent KCHOn in mushroom 
decoction. 

£ per cent MgHPO a in mush- 
room decoction. 

Decoction of mushrooms 

Living tissue of mushroom in 
mushroom decoction. 

do 



10 spores 

fa— 1 spore . . . 
Vj— None 

None 

a — 10 spores . 

None 

2 spores 



Few spores . 
do 



fa— None . 
\b~ None.. 
10 spores . 

....do.... 

....do.... 



None 

10 spores . 

None 

10 spores . 

do 

do.... 



None. 



.do. 



Few spores . . 
1 or 2 spores . 
Few spores . . 



10-50 per cent . 
Few spores 



2 per cent . . . 

10 spores 

5-8 per cent . 
2-3 per cent . 



J-l-2 per cent 

fa— 2 per cent 

\b— Very few spores . 

a— Few spores a 

b — None" 

\a— Fewsporesa 

\6— Noneb 



50 per cent. 

3 per cent. 

None, 
f Do. 
U per cent. 

Germinated spores badly 
injured. 

None. 

As before; injured. 

5 per cent. 
Do. 

Few spores. 
10 per cent. 
As before; injured. 

5-10 per cent. 

2-5 per cent. 

1-2 percent. 
Injured. 
1-2 per cent. 
10-50 per cent. 

1 per cent. 
1-2 per cent. 

None. 

Do. 

Injured. 

Few spores. 

2-5 per cent. 

10-20 per cent. 
Contaminated. 

Contaminated; 5 per 

cent, but injured. 
3-5 per cent; injured. 

10 per cent. 

10-20 per cent. 

fa— 5 per cent. 
[b— Contaminated 

2 per cent. 
1-2 per cent. 
12 spores. 



As before. 
None. 



" In this cell the tissue developed a new growth. 
'' Xo growth from tissue introduced. 



On account of the fact that magnesium phosphite and magnesium 
potassium ammonium phosphate had in most cases proved to be 
stimuli for germination, experiments were next made to determine 
the efficiency of these salts on various media, as indicated in the 
table on the following page. 



GERMINATION STUDIES. 
Table II. — Efficiency of salts on various media. 



17 



Nature of compost. 


Appearance after 26 days. 


Nature of compost. 


Appearance after 25 days. 


Well-rotted stable 
manure." 
Do.b 


No growth. 

Fine growth. 

One. fair growth: one, 

good growth. 
No growth. 

One, good growth; one, 

slight growth. 
One, good growth*; one, 

fine growth. 
One, good growth; one, 

slight growth. 


Well-rotted cow ma- 
nure. & 

Peaty mold" 

Do.'' 


Good growth. 
No growth. 


Half-rotted stable 
manure. " 
Do 6 


Maryland peat " 

Do.'< 


Do. 
Do. 


Fresh stable manure" 


Well-rotted Ginkgo 
leaf mold." 
Do.'' 


Do. 
Do. 


Do.'' 


Cot ton-seed motes". 
Do.'' 


One, no growth; one, fine 
growth. 


nure." 







" Watered with concentrated solution of magnesium phosphite. 

" Watered with strong solution of magnesium potassium ammonium phosphate. 

Large test tubes were used in these experiments, and duplicate 
cultures were made in every instance. From these and from numer- 
ous other cultures it was ascertained that germination could not be 
obtained invariably, even on favorable media and under pure-culture 
conditions, by the use of these partial stimuli. Nevertheless, the 
percentage of failures has usually been small. By means of the 
stimulus given by magnesium phosphite it has also been possible to 
get growth from the spores in test-tube cultures with gray filter 
paper as the solid substratum and various plant decoctions and cul- 
ture solutions as the nutrients. Details of these results, however, 
may be omitted. 

In many cases it has been possible to obtain growth from the 
spores by the use of the stimulating salts which have been mentioned 
in connection with the germination studies. Where it is desired to 
make experiments along this line the writer has found it more 
practicable to use spores from a mushroom as young as possible. 
If one takes a mushroom just at the time that the veil is breaking, 
inoculations may be readily made from the spores and few contami- 
nations will result. In this case, by means of a sterile needle, or 
scalpel, a few spores may be removed from the spore-bearing, or 
gill, surface and these may be transferred to the tubes in the same 
way as were bits of the fresh tissue. It is also possible to secure a 
spore print from a mushroom the gill surface of which has not been 
exposed to germs of the atmosphere. In the latter case it is desir- 
able to remove stem and partial veil, peel off the incurved edges of 
the cap which have been in contact with the soil, and place the cap, 
gill surface downward, in a sterilized dish or on sterile paper. If 
this is then kept free from dust, a spore print may be obtained, which 
should not be contaminated by foreign germs. This print may then 
be used in making a large number of spore cultures. 

Experiments were also made in which pots of unsterile composts 
and manures were inoculated, on the one hand, with spores, and, on 



18 



MUSHROOM GROWING AND SPAWN MAKING. 



the other hand, for control purposes, with spawn from pure cultures. 
The duration of the experiments was two months. Some of these 
pots were watered with a mineral nutrient solution including as one 
constituent magnesium phosphite, designated X, others with the same 
solution to which was also added a small quantity of dried blood, 
designated Y, and the remainder with pure water. The results are 
tabulated as follows: 

Table III. — Extent of growth of spores and spawn in pots. 



Spores 
Spores 
Spawn 
Spawn 
Spawn 



Cattle ma- 
nure, old. 







Fresh stable 

manure 

and sand. 



None 

do 

Very good . 

Slight!""" 

do 

None 

do Slight 

Slight do 



Stable 
manure. 



Old stable 
manure 
and sand. 



None 

...do.... 
...do.... 
...do.... 



.do None- 



Slight 

do 

....do. 
...do 

None I do 

Slight.... ...do 

Good ' do 

d.. 

do 



do. 



Old stable 
manure. 



None. 
...do. 
...do. 
-.do- 
...do. 
...do. 
...do. 
... do. 
...do. 
...do. 



Fertilizer. 



Y. 
Y. 
X. 
X 
Y. 
Y. 
X. 
X. 

None. 
Do. 



TISSUE CULTURES. 



The suggestion which had presented itself of using bits of living 
tissue from a sporophore instead of spores seemed also, from general 
observations, to be of sufficient importance to warrant a thorough 
trial. During moist weather, or in a moist cellar where mushrooms 
are being grown, one will frequently find that an injury in a young 
mushroom is rapidly healed by a growth of hyphse from the edges 
of the injured area. The same thing had been noted in the open in 
the case of puffballs. In many instances, moreover, pure cultures 
of fungi in other groups have been obtained by the use of small bits 
of a sclerotial mass of tissue. Accordingly, a young sporophore of 
Agaricus campestris was obtained, and after breaking it open longi- 
tudinally a number of pieces of tissue from within were carefully 
removed with a sterile scalpel to a sterile Petri dish. A number of 
cultures were then made by this tissue-culture method on a variety 
of nutrient media, such as bean pods, manure, leaf mold, etc. From 
this and from numerous other similar tests it was ascertained that 
when the mushrooms, from which the nocules of tissue are taken, 
are young and healthy, there is seldom an instance in which growth 
does not result. It was easily shown that failure to grow was gen- 
erally due to the advanced age of the mushroom used, to an unfavor- 
able medium, or to bacterial contamination. 

The first successful pure cultures were made by this method during 
the early spring of 1902 from mushrooms grown indoors. During 



TISSUE CULTURES. 



19 



the following summer, or as other fleshy fungi appeared in the open, 
cultures were made from other forms in order to determine the 
general applicability of the method. The experiments were success- 
ful in most cases, although it was found almost impossible to obtain 
certain species of fungi in a condition young enough to be free from 
bacterial infestation. In general, the method seemed to commend 
itself strongly as a means of procuring pure cultures of desirable 
edible species, particularly of those species the spores of which could 
not be obtained pure or which could not be readily germinated. 

During the two subsequent seasons this method has been employed 
with a great variety of fungi representing many natural orders. No 
systematic endeavor has been made to determine the limitations of 
the tissue-culture method as applied to Basidiomycetes, but, inci- 
dental to the general studies, cultures have been made from forms 
differing very widely, not only in relationship but also in texture and 
in habitat. 

In all there is a record of 69 species having been tested upon one 
or another medium. In a few cases the cultures have invariably been 
contaminated, and it is to be supposed, perhaps, that the plants were 
collected in a condition too old for the purpose in hand. In only 
about ten forms has it seemed that there is no evident reason for the 
failure to develop mycelium. Of the remainder fully 10 have grown 
promptly on the media employed. The table following indicates the 
names of the species employed and the results obtained. It must be 
said, however, that cultures of a number of species were made of 
which no record was kept ; among these, also, some grew and some 
failed. 

Table IV. — Results obtained from different species. 



Fundus. 


Num- 
ber of 

cul- 
tures." 


Substratum. 


Result. 




Few. 

1 
oc 

cc 

cc 

1 

Few. 

1 
2 
2 
2 
cc 
2 
2 
1 
2 

Few. 

Few. 
cc 

Few. 


Beans, manure, leaves, etc 


Rapid growth. 




Agaricus campestris (various 
varieties). 


Beans, manure, leaves, etc 

do 


Rapid growth. 
Do. 


Agaricus fabaceus var 


....do... 


Do. 




Some growth. 
Rapid growth. 


Agaricus villaticus 


Manure, leaves, etc. 






Do. 




do 


Do. 




.do. 


Do 


Armillaria mellea 


Beans, leaves, dead wood, etc. . . 


Rapid growth. 




do .... 






do 


Do. 




do 








Rapid growth. 
Do. 
Do. 


Calvatia craniiformis . 


do 

Beans, leaves, soil, etc 




Do. 




1 






Clavaria forroosa . 


1 do 


Do. 



a cc indicates an indefinite number. 



20 



MUSHROOM GROWING AND SPAWN MAKING. 



Table IV. — Results obtained from different species — Continued. 



Fungus. 



Num- 
ber of 
cul- 
tures. 



Substratum. 



Result. 



Clitocybe illudens 

Clitoeybe sp.? 

Clitopilus prunulus 

Collybia platyphylia . 

Collybia radicata... 

Collybia velutipes 

Coprinua atrainentarius . . . 

Copriuus comatus 

Copriuus rimetarius 

Coprinus mieaeeus 

Cortinarius arinillatus 

Cortinarius castaneus 

Cortinarius sp.? 

Daedalia quercina. ._ 

Hydnum caput medusae. .. 

Hydnum coralloides 

Hydnum erinaceum 

Lactarius corrugis (?) 

Lactarius piperatus 

Lactarius volemus 

Do 

Lepiota americana 

Lepiota rnorgani 

Lepiota procera 

Lepiota rhacodes 

Lycoperdon gemmatum . . . 

Lycoperdon wrigbt ii 

Morchella esculenta 

Pluteus cervinus 

Pleurotus ostreatus 

Pletirotus ulmarius 

Pboliotaadiposa 

Polyporus betulinus 

Polypi >rus inty baceus 

P< >lyporus sulphureus 

Polystictus cinnabarinus _. 

Russula adusta 

Russula emetica 

Russula sp 

Russula sordida 

Russula virescens 

Secotium acuminatum 

Strobilomyces strobilaceus 

Stropharia sp 

Tremella mycetopbila 

Tricholoma personatum . . . 
Tricboloma russula _ 



2 

Few. 

1 

Few. 

1 

cc 

cc 

Few. 

cc 

1 

1 

Few. 

Few. 

1 

2 

?. 

Few. 

cc 

1 



cc 

Few. 

■2 

1 

2 

Few. 

cc 

1 

1 

1 

1 

2 

2 

1 



Few. 

1 
Few. 

2 

1 
1 
1 
1 
2 



Beans 

do 

Beans, manure, etc 

Beans 

do 

....do 

Beans, leaves, manure, etc . 
Beans, manure, leaves, etc. 

Beans, leaves 

Beans, leaves, manure, etc. 

Beans 

do 

Beans, leaves, manure" 

Beans, leaves, manure, etc. 

Beans _ 

do.. 

do.. 

Beans and leaves 

....do 

Acid beans 

Beans 

do 

do 

Beans, leaves, etc 

do 

Beans 

Sod. 



Beans and leaves 

do 

Beans, leaves, mamire, ete. 

Beans _ 

Beans and leaves 

Beans 

do. 

Beans and leaves 

do 

Beans 

Beans, etc 



Beans 

do 

do 

do 

do 

do 

do 

Beans and manure . 
Beans and leaves . . . 



Some growth. 
Rapid growth. 
Some grew well. 
No growth. 
Good growth. 

Do. 
Rapid growth. 

Do. 

Do. 

Do. 
Contaminated. 

Do. 
Good growth. 
Rapid growth. 
Good growth. 

Do. 

Do. 
Slight growth, one. 
No growth. 
Some growth. 
No growth. 

Do. 
Some growth. 
Rapid growth. 

Do. 
Good growth. 

Do. 

Do. 
Some growth. 
Rapid growth. 

Do. 
No growth. 
Slow growth. 

Do. 
Rapid growth. 
Good growth. 
No growth. 
Often contaminated 

but some grew. 
No growth. 

Do. 

Do. 
Slow growth. 
No growth. 
Contaminated. 
No growth. 
Good growth. 

Do. 



It is not to be understood that the failures recorded in the forego- 
ing table indicate that these species will not grow. The evidence is 
that they did not grow upon the media used, and it is very probable 
that most of these could be propagated in culture by this method if 
a systematic attempt were made to determine what substrata are 
desirable. The writer believes that this statement holds true particu- 
larly in the case of certain species of Boletus. No attempt was 
made to cultivate Boleti in any other way than upon bean pods. A 
few mycelial threads were developed in such cases, but these failed 
to grow upon the bean, apparently dying before even the nutrients 
in the fragment of tissue were exhausted. 

It is interesting to note that many of the fungi which have given 
good growth have not hitherto been grown in pure culture. Accord- 
's Costaiitin et Matruchot. Sur la production ilu mycelium des champignon 
superieurs. Extrait Compt. Rend. d. .Seances de la Soc. de Ltiologie. January, 



TISSUE CULTURES. 21 

ing to Costantin and Matruchot," Van Tieghem (1S7C>) produced the 
mycelium of Coprinus in pure culture. Later, Brefeld ° accom- 
plished the same result with many species of Coprinus. and also with 
Armillaria mettea. Costantin has also published a number of brief 
papers, or announcements, of successful cultures upon artificial media 
of the mycelium of several fleshy fungi. Besides Agaricus campestris, 
he has grown the mycelium of Amanita rubescens, Armillaria mellea, 
Collybia velntipes, Lepiota procera, Marasmius oreades, Tricholoma 
nudum, Pleurotus ostreatus, Pholiota aegerita, Coprinus comatus, 
Polyporus tuberaster, P. frondosus, Hydnum coraUoides, Morchella 
esculenta, and perhaps a few others. He has also grown to maturity 
sporophores of Agaricus campestris, Coprinus comatus, and Tri- 
choloma nudum. Unfortunately, Costantin seldom indicates the 
substratum upon which his cultures were made. Falck '' reports 
having produced in culture the sporophores of Collybia vehitipes, 
Phlebia merismoides, Hypholoma fasciculate, Chalymotta campanu- 
lata, and Coprinus ephemeras in his studies upon the connection of 
oidial stages with perfect forms of the Basidiomycetes. In the work 
of the writer so far no special attempt has been made to obtain the 
sporophores of the fungi cultivated except in the case of Agaricus 
campestris. Nevertheless, the following species have fruited in pure 
culture upon the media indicated : 

Medium. 

Agaricus campestris - Manure. 

Agaricus fabaceus Manure. 

Agaricus amygdalinus Manure. 

Armillaria mellea Beans. 

Bovistella obiensis Soil. 

Oalvatia cyathiforme Soil. 

Calvatia rubro-flava Soil. 

Cortinarius sp Soil. 

Coprinus comatus Leaves. 

Coprinus flmetarius Leaves. 

Coprinus solstitialis (?) Leaves, etc. 

Daedalia quercina Leaves, etc. 

Hydnum coralloides Beans. 

Lycoperdon wrightii Soil. 

Pleurotus ostreatus Beans and manure. 

Pleurotus ulmarius Manure. 

In some instances the sporophores have been minute, owing to the 
small quantity of the culture medium. 

o Brefeld. O. Unters. aus d. Gesammtgebiete d. Mykologie, 8, 0. 10. 

& Falck, R. Die Cultur der Oidien und die Riickfiibrung in die biibere Frucb:- 
form bei den Basidiomyceten. Cohn's Beitrage zur Biologie der Pflauzen, 8: 
307-346 (Pis. 12-17). 



22 MUSHROOM GROWING AND SPAWN MAKING. 

From the standpoint of obtaining pure cultures, the tissue-culture 
method is capable of very general application. Three considerations 
render it particularly important, as follows: (1) When a suitable 
culture medium is at hand, a pure culture may be obtained almost 
invariably from a young, healthy plant. (2) Cultures may be made 
from fungi the spores of which have never been brought to germina- 
tion. (3) Pure cultures are made by direct inoculation; that is, 
dilution cultures are rendered wholly superfluous. In the case of 
Agarkus campestris and other Basidiomycetes, in which the gill- 
bearing surface is protected until the spores are produced, it is pos- 
sible, with the precautions previously mentioned, to obtain the spores 
pure, or practically pure, and at the same time in considerable quan- 
tity. This is not possible with the great majority of fleshy fungi, 
which are truly gymnocarpous. Again, members of the genus Cop- 
rinus are deliquescent, and here it is impracticable to secure spores 
by the spore-print method. In the Lycoperdacea? and other Gaster- 
omycetes it has been found that bacteria are frequently present in the 
tissues by the time the spores are formed, and, even if the spores 
could be germinated, direct cultures would perhaps be seldom possi- 
ble. By the tissue method it is only necessary that the plant shall be 
so young that the cells of the tissue are capable of growth and that 
there are no foreign organisms present in the tissue. In this connec- 
tion it may be stated that in the Phallinea\ Hymenogastrinea;, and 
Lycoperdinea. 1 no representative has been germinated, while in the 
Plectobasidineae germination is known only in the case of Sphaero- 
bolus stellatus and Pisolithus crassipes. 

When the natural conditions of germination shall have been more 
definitely ascertained, direct spore-culture methods should in prac- 
tice, perhajDS, replace the pure tissue-culture methods in making 
virgin spawn. This would render unnecessary a tedious portion of 
the work, and the process of spawn making would be thereby made 
less expensive. 

A discussion of the respective practical merits of the spore and tissue 
methods would not be complete without reference to the comparative 
vigor, or productive power, of the resulting mycelium. In the growth 
of the mycelium no difference could be detected. The writer has also 
grown mushrooms from spawn produced by both of these methods; 
but the results do not indicate that there is any advantage for the one 
over the other. It is believed, therefore, that the processes of basidial 
and spore formation are in this regard relatively unessential, or at 
least do not intensify whatever invigoration may, in general, result 
from mere sporophore production. It is to be expected, perhaps, that 
any and all cells of the sporophore may be invigorated by whatever 
is to be gained by the assemblage, or concentration, in the ditferen- 



NUTRITION. 23 

Hated sporophore, of food products collected by a ramifying myce- 
lium. According to the studies of Harper, Maire,'' and others, there 
is no sexual fusion in the case of the Basidiomycetes which have been 
studied. Two nuclei are present in the cells of the sporophore, but 
these are associated conjugate nuclei, and the fusion of these in the 
basidhun is generally considered in no sense an act of fertilization, 
but rather a form of nuclear reduction. Maire states that the cells of 
the mycelium obtained by the germination of the basidiospore are 
uninucleate. It has not yet been ascertained when or how the binu- 
cleate condition arises. 

NUTRITION. 

Although Agaricus campestris has been cultivated for so long a 
time, it does not seem that it has previously been subjected to careful 
experimentation from the point of view of nutrition. The belief 
generally prevalent is that the most essential factor in the nutrition 
of the mushroom is the " ammonia " of the manure or compost. 
Again, it is claimed that organic waste products, such as those indi- 
cated, must undergo a process of fermentation, or " preparation," 
in order to furnish the necessary nutrients for the growing mycelium. 
This idea, as will be seen later, is merely based upon casual observa- 
tions " in nature," and it is found wholly erroneous when tested for 
its fundamental worth by the elimination of other factors of the com- 
post environment. 

Growth on manure and other complex media. — Early in this inves- 
tigation it was ascertained that the mycelium of Agaricus campestris 
in pure cultures would grow luxuriantly on fresh stable manure, and 
as a rule upon the same product in any stage of fermentation or 
decomposition. In some instances, undoubtedly, fresh manure may 
contain injurious compounds; somewhat oftener the same is true for 
the fermented product. In some instances it is desirable to dry or 
thoroughly air the fresh manure before use. Fresh manure from 
grass-fed animals is not to be recommended. The mycelium also 
grows luxuriantly on bean stems or jiods, n half-rotted leaves of 
deciduous trees, on rich soil, on well-rotted sawdust, and on a variety 
of other substances. It does not grow readily upon peaty products. 

Some of the more promising edible species were cultivated in 
various media in order to obtain an idea of the comparative value of 
these media in furnishing a nutrient to particular forms. It is not 
possible, of course, to base definite conclusions upon results obtained 

"Harper, R. A. Binuclente cells in certain Hymenomycetes. Bot. Gaz., 
,3.3: 1-25. 1002. 

' .Maire, R. Recherches cytologiques et taxonoiniques sur les Basidiomycetes. 
Bui. Soc. Myc. de France, 18 : 1-200. 1002. 



24 MUSHROOM GROWING AND SPAWN MAKING. 

from pure cultures, since the presence of particular foreign organisms 
in the substratum under natural conditions is perhaps quite as im- 
portant a consideration as that of the specific nutrient value of the 
substratum. The following results are, however, suggestive : 

1. Agaricus campestris. 

Leaves — good growth throughout. 

Soil — fair growth, with tendency to become threaded early. 

Manure — good growth throughout. 

Beans — good growth throughout. 

Sugar beet — fair growth, spreading very slowly. 

Potato — slight growth, spreading very slowly. 

Corn meal — slight growth, spreading slowly, soon becoming brown. 

2. Agaricus fabaceus. 

Leaves — very good growth, rapidly filling tube. 
Soil — good growth, but slower than the above. 
Manure — good growth, but slower than the above. 
Beans — very dense growth, soon filling whole tube. 

Sugar beet — good growth : somewhat less rapid and abundant than the 
above. 

3. Agaricus villatlcus. 

Practically the same as Agaricus campestris. 

4. Agaricus fabaceus var. 

Practically the same as Agaricus fabaceus. 

5. Bovistella ohiensis. 

Leaves — good growth throughout. 
Soil — growth throughout, but sparse and threadlike. 
Manure — good growth throughout. 
Beans — good growth : appressed. 
Sugar beet — very slight growth, 
(i. Calvatia cyathiforme. 

Leaves — very good growth throughout. 
Soil — good growth ; quite as rapid as above. 
Manure — practically no growth. 
Beans — good growth, but spreads very slowly. 
Sugar beet — slight growth. 

7. Calvatia crauiiforniis. 

Practically the same as above. 

8. Calvatia rubro-flava. 

Practically the same as in the other species of this genus, but spreads 
somewhat more slowly on soil. 

9. Coprinus atramentarius. 

Leaves — very good growth throughout. 
Soil — slight growth. 
Manure — fair growth, but very slow. 
Beans — very good growth. 
10. Coprinus comatus. 

Leaves — very good growth throughout ; rapid. 
Soil — good growth. 

Manure — very good growth throughout; rapid. 
Beans — very good growth throughout ; rapid. 
Sugar beet — very slow growth. 



NUTRITION, 25 

11. Lepiota rhacodes. 

Leaves — very good growth. 

Soil — slight growth. 

Manure — slight growth. 

Beans — very good growth throughout 

Sugar beet — very good growth throughout. 

12. Morchella esculenta. 

Leaves — very good growth: mycelium never dense. 

Soil — very little growth. 

Manure — very slight growth. 

Beans — very good growth. 

Sugar beet — good growth, but slower than above. 

13. I'leurotus ostreatus. 

Leaves very g (growth; rapid. 

Soil — fair growth. 

Manure — good growth. 

Beans — very good growth: rapid. 

Sugar beet — slight growth ; very slow. 

14. I'leurotus ulmarius. 

Practically the same as I'leurotus ostreatus. 

15. Polyporus sulphureus. 

Leaves — fair growth; abundant, tilling tube. 
Soil — fair growth. 

Manure — fair growth, but very slow. 
Beans — very good growth, rapidly tilling tube. 

Sugar beet — fair growth : much lighter mycelium than the above, with 
prompt oidial development. 
Hi. Trieholoma personatum. 

Leaves — very good growth throughout. 
Soil — very good growth throughout. 
Manure — growth slow, but eventually good. 
Beans — good growth throughout. 

Plates II, III, and IV show some of the more important of these 

species. 

Taking into consideration the variable quality of the stable manure 
which may be obtained at all seasons, the value of half-rotted decid- 
uous leaves as a substratum for Basidiomycetes is worthy of special 
emphasis. The writer has found such material more readily sterilized 
than manure, and usually more prompt than the latter to give growth. 

In order to test in pure cultures the probable effect of fertilizers 
as indicated by any marked increase in the rapidity of growth of the 
mycelium, experiments were made by adding a small quantity of 
ordinary nutrient salts to test tubes containing manure. A chlorid 
and a nitrate of the following salts were employed, viz, ammonium, 
calcium, magnesium, and potassium. In addition, dibasic potassium 
phosphate and also sodium chlorid. as well as control cultures, were 
used. Three tubes were employed with each of the compounds men- 
tioned. There was no marked difference in the amount or rapidity 
of the growth noted, as found by comparing the averages of growth. 



26 



MUSHROOM GROWING AND SPAWN MAKING. 



It seemed possible, however, that some slight advantage resulted from 
the calcium compounds, but there was no pronounced benefit in any 
lube. Further reference is made to the use of nutrient salts in mush- 
room growing in another chapter. 

Growth on chemically known media. — In an attempt to determine 
somewhat more accurately the value of different compounds as 
nutrients, particularly carbohydrate and nitrogenous substances, sev- 
eral series of extensive tests have been made with Agaricus campes- 
tris, and also with Agaricus fdbaceus and Coprinus comatus. These 
fungi do not grow readily in liquid media, and it has been difficult 
to obtain a wholly reliable and satisfactory substratum, one which 
would itself be practically pure, or well known, chemically, and at 
the same time effective for its purpose. After unsatisfactory at- 
tempts with various gelatinous solid media, with charcoal, etc., it was 
decided that the commercial gray filter paper had more to recom- 
mend it than any other substance suggested. Accordingly, all ex- 
periments were made in Erlenmeyer flasks of 150 c. c. capacity, and 
in each flask was placed about (> grams of this paper wadded into 
pellets. The latter was moistened in each case with the nutrient 
solution used. The flasks were subsequently sterilized in the auto- 
clave and then inoculated with a very minute fragment of straw 
with the fresh mycelium from a pure culture on manure. 

Tabulation of special results. — In the following tables are given 
the results of two out of several series of experiments, wdiich have 
been conducted in order to throw some light on the point just dis- 
cussed. These tables include, also, many cultures on media of un- 
known composition. 

Table V. — Results of growth mi media — First series of experiments. 



No. 



Medium. 



Extent of growth. 



3b 
4a 
4b 
">a 
5b 
6a 
(ib 
7a 
7b 
8a 
8b 
Ha 
9b 
Ilia 
lnb 
11a 
lib 
12a 
12b 
13a 
13b 



}Dt. H.O 

(•Solution A 

[Solution A and cane sugar, H per cent __.__. 

■Cane sugar, U per cent 

[Solution A and lactose, U per cent 

SVLactose, U per cent 
Solution A and glycerin, l.J per cent. '_. 

[Glycerin, 1.} percent 

j-Solution A and starch paste, I per cent 

[■Starch paste, A per cent 

[Solution A and starch, * per cent, and diastase, trace 

[Starch, A per cent, and diastase, trace 

[Solution A and dextrose, 1 .1 per cent 



(Very slight. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 
air growth 

Do. 

Do. 

Do. 

(Contaminated, discarded. 
IFair. 
IQood. 
\ Do. 
I Very slight. 
lOoo'd. 



jFi 



NUTRITION. 27 

Table V. — Results of growth on mrilin — First series of experiments — Continued. 



No. 



Medium. 



Extent of growth. 



14a 
14b 
15a 
15b 
16a 
16b 

17a 
17b 

18a 
18b 
I'.ta 
19b 
Li la 
20b 
21a 
21b 
22a 
22b 
23a 
23b 
24a 
24b 
25a 
25b 
26a 
2tib 
27a 
27 b 
28a 
28b 
29a 
29b 
30a 
:;m, 
31a 
31b 
32a 
32b 
33a 
33b 
34a 
34b 
35a 
35b 
36a 
36b 
37a 
37b 
38a 
38b 
39a 
39b 
40a 
40b 
41a 
41b 
42a 
42b 
43a 
43b 
44a 
44b 
45a 
45b 
46a 
46b 
47a 
47b 
4Sa 
4Sb 
49a 
49b 
50a 
50b 
51a 
52a 
53b 
53a 
53b 
54a 
54b 
55a 
55b 



Dextrose, H per cent 

Solution A and niannite, lj percent 

Manuite, 1J per cent 

[Solution A and maltose, 11 per ceut 

[■Maltose. 1 ] per cent ._ 

[■Solution A and potassium tartrate, i per cent. . . 

[Potassium tartrate. \ per cent 

[Solution A and magnesium tartrate, ) per cent. 

! Magnesium tartrate, i per cent 

Solution A and ammonium tartrate, $ per cent, 
[Ammonium tartrate, i per cent. 

! ^Solution A and potassium lactate, i per cent. 
Potassium lactate, \ per cent 

•Solution A and magnesium lactate, i per cent . . 

[Magnesium lactate. } per cent 

[Solution A and ammonium lactate, J per cent . . . 
[Ammonium lactate, I per cent 



(Slight. 
' \ Do. 

Very slight. 

Lost. 

{Contaminated with Asper- 
gillus. Fair growth, yel- 
lowish in color. 
(Fair. 
\ Do. 
J Slight. 
1 Do. 
/ Do. 
\ Do. 
I Do. 
\ Do. 
I Do. 

I Do. 
I Do. 
I Do. 
/ Do. 

■|1 Do. 
il Do. 
li Do. 

I I Do. 

(Slight to fair. 
1 1 Slight. 

I Do. 

Do. 

Do. 

air to good. 

Do. 

/Slight. 



I 



Solution A and cak'hini hippurate, i per eent. 



I 
I 
[Calcium hippurate. i per cent. ?. 

[■Solution A and asparagin, J per cent 

^Asparagin. 1 per cent 

[•Solution A and peptone, ) per cent 

^Peptone, £ per cent .. -. 

'•Solution A and casein, 1 per cent 

>Casein, | per cent - - 

[•Solution A and pepsin, i per cent.. 

■Pepsin, i per cent 

[■Solution B - 

[■Solution B and asparagin, i per cent 

[•Solution B and peptone, l per cent . . 

[■Solution B and casein, \ per cent - 

Solution B and pepsin, i per cent 

■Bouillon - 

■Bean decoction 

Beet decoction 

[•Manure decoction . _ 

[■Manure 

Wheat straw . 

jSolution A and wheat straw 

[•Solution B and wheat straw 

[•Solution B and NH 4 NO a and cane sugar 

^Solution B and cane sugar and Ca(N0 3 )«, i per cent. 



L Do. 
) Very £ 



R 



I Very good. 

(Slight.' 
t Do. 
I Do. 
1 Do. 
f Do. 
\ Do. 
/Good. 
Do. 
ery slight. 

Very good. 

Do! 
\ Do. 
I Slight to fair. 
t Do. 

Do. 

Do. 

Do. 

Do. 
(Slight. 
\ Do. 
(Very slight. 

/Very good. 

(Culture lost. 
\ Do. 
I Slight to fair. 
I Do. 
/Very good. 

Do. 
Good to very good. 

Do. 
Very good. 

Do. 

Do. 

Do. 
ost. 

Do. 

Do. 

Do. 

Do. 
(Slight to fair, 
t Do. 
(Very slight. 



28 MUSHROOM GROWING AND SPAWN MAKING. 

Table V. — Results of growth on media — First series of experiments — Continued. 



No. 



Medium. 



Extent of growth. 



56b [Solution B and sugar and Mg(N0 3 ) = , J per cent 

57b ' [Solution B and sugar and NH.,C1, i per cent . 

^ ilsolution B and NH4N0 3 , i per cent 

59b '[Solution B and Ca(N0 3 )., i per cent . 
60a 



JJ)g ^Solution B and Mg(N0 3 t : , J per cent 

61b '[Solution B and NH 4 C1, 1 per cent 

62b [Mushroom decoction 



/Very slight. 

Do! 
Do. 
Do. 
Do. 
Do. 

n Do. 
; Do. 

\ Do. 
I Slight to fair 
\ Do. 
I Do. 
\ Do. 



Table VI. — Results of growth on media — Second xn-iex of experiments. 



No. 



Medium. 



Extent of growth. 



la 
lb 
2a 
2b 
3a 
3b 
4a 
4b 
5a 
5b 
6a 
6b 
7a 
7b 
8a 
8b 
9a 
9b 
10a 
10b 
11a 
lib 
12a 
12b 
13a 
13b 
14a 
14b 
15a 
15b 
16a 
16b 
17a 
17b 
18a 
18b 
19a 
19b 
20a 
20b 
21a 
21b 
22a 
23a 
23b 
24a 
24b 
25a 
25b 
26a 
26b 
27a 
27b 
28a 
28b 
29a 
29b 



■Fresh horse manure (grass-fed animals) 

[Fresh horse manure, thoroughly washed, residue only used 

[Filtrate, or liquid resulting from washing No. 2. 

[Decoction of fresh horse manure, as in No. 1 

-Fermented horse manure, thoroughly washed 

[Filtrate or washing from No. 5 l_ 

[Rotted stable manure _ 

[Decoction of green timothy hay * 

[Residue from decoction in No. 8 

[strong bean juice 

[Weak bean juice 

[Strong decoction of mushrooms _ 

[One-half strength decoction of mushrooms 

[weak decoction of mushrooms 

■Oat straw - 

[■Wheat straw 

[Corn meal _ 

W gram cane sugar in 25 c.<\ solution A 

U gram milk sugar in 25 c. c. solution A 

U gram galactose in 25 c. c. solution A 

U gram cornstarch in 25 c. c. solution A 

i strength albumen (egg) - 

[i gram glucose in 25 c. c. solution A 

[t gram dextrose in 25 c. c. solution A 

[i gram mannite in 25 c. c. solution A 

i gram glycogen in 25 c. c. solution A - 

i gram maltose in 25 c. c. solution A 

[i gram levulose in 25 c. c. solution A 

U gram glycerin in 25 c. c. solution A 



(None. 
lSlight. 

(Contaminated. 
\Good. 
IGood. 

[Contaminated. 
Fair. 
Do. 



I Very good. 

ISlight.' 

1 Do. 

IGood. 

(Contaminated. 

(Good. 

1 Do. 

/None. 

Do. 
ISlight, 

(Contaminated. 
(Good, 
i Do. 
ISlight. 
i Do. 

Slight. 

Contaminated. 
(Slight. 
1 Do. 
(Contaminated. 
\Sligbt, 
IGood. 
\ Do. 
iFair. 
\ Do. 
ISlight, 

[Confined ti> nocules. 
f Do. 

(Slight throughout, 
f Do. 

[Slight, but contaminated. 
ISlight at top. 
\Lost. 

Confined to nocules. 
ISlight at top. 
i Do. 

(Fair throughout. 
\ Do. 
(Fair. 

(Contaminated. 
(Slight; contaminated. 
[Fair. 

ISlight at top. 
i Do. 
/Slight, 
\Slight at top. 

Confined to nocules. 



NUTRITION. 29 

Table VI. — Results of growth on media — Second series of experiments — Cont'd. 



No. 



Medium. 



Extent of growth. 



311a 
30b 
31a 
31b 
32a 
32b 
33a 
33b 
34a 
1Mb 
35a 
35b 
36a 
36b 
37a 
37b 
38a 
38b 
39a 
39b 
40a 
40b 
41a 
41b 
42a 
42b 
43a 
43b 
44a 
44b 
45a 
46b 
46a 
46b 
47a 
47b 
48a 
48b 
49a 
49b 
50a 
50b 
51a 
51b 
52a 
52b 
53a 
53b 
54a 
54b 
55a 
55b 
56a 
56b 
57a 
57b 
58a 
r,sl, 
59a 
59b 
60a 
60b 
61a 
61b 
62a 
62b 
63a 
63b 
64a 
64b 

65a 
65b 

66a 
66b 
67a 
67b 
68a 
68b 



H gram potassium tartrate in 25 c. o. solution A 

[i gram magnesium tartrate in 25 c. c. solution A 

[i gram potassium lactate in 25 c. c. solution A 

H gram potassium lactophosphate in 25 c. c. solution A. 

[i gram magnesium citrate in 25 c. c. solution A 

[i gram magnesium inalate in 25 c. c. solution A 

[i gram calcium hippurate in 25 c. c. solution A 

U gram asparagin in solution A 

[i gram urea in solution A 

U gram peptone in solution A 

i gram casein in solution A 

;4 gram benzoic acid in solution A 

ji gram benzoic acid in solution A 

[Solution A 

[Solution B 



[■Distilled HO 

[■Decoction from productive old bed. 
[Oak sawdust, only slightly rotted . . 

[Gluten meal and water 

[Cotton-seed meal and water _. 

[Cotton-seed meal 

■J gram asparagin in solution B 

[t gram asparagin in solution B 



I gram urea in solution B 

d gram urea in solution B 

U gram urea in solution B 

U gram peptone in 25 c. c. solution B 

[i gram peptone in 25 c. c. solution B 

H gram peptone in 25 c. c. solution B 

[j gram peptone and A gram NaN0 3 in solution B. 

H gram casein in 25 c. c. solution B 

U gram casein in 25 c. c. solution B 

h's gram casein in 25 c. c. solution B 

H strength albumen (egg) 

[oil meal and water 

[White pine shavings 

["White pine shavings with bean decoction 

[Asbestos with bean decoction 

joid flake spawn 



(Veryslight: contaminated. 

t bo. 

[Confined to nocules. 

1 Do. 

I Do. 

1 Do. 

(Slight at top. 

Do. 

Do. 

Do. 

Do. 

Do. 
Good top. 

Do. 
Slight. 
I Do. 

I Confined to nocules. 
\ Do. 
Fair at top. 

Do. 
air throughout. 

Do. 
/None, 
t Do. 
( Do. 
\ Do. 

(Confined to nocules. 
\ Do. 

Do. 

Do. 

Do. 

Do. 
air throughout. 

Do. 
(Confined to nocules. 
i Do. 

/Good throughout. 
\ Do. 
(Contaminated . 
i Do. 
(Slight at top. 
1 Contaminated. 
(Slight at top. 
\ Do. 
(Fail-. 
\ Do. 
(None. 
\ Do. 
(Slight at top. 
\ Do. 

(Slight throughout, 
t Do. 
(Slight at top. 
t Do. 
f Do. 
1 Do. 
(Fair at top. 
\ Do. 

fFair throughout. 
(Slight. 
~ery slight. 

(Fair at top. 
tSlight at top. 
(Fair throughout. 
\ Do. 
ISlight at top. 
1 Do. 

/Good throughout. 
\ Do. 

Very small area, but copi- 
ous. 
Do. 
Do. 
Do. 

Confined to nocules. 
Do. 
ery good. 



30 MUSHROOM GKOWING AND SPAWN MAKING. 

It is not possible here to enter into a detailed discussion of the 
results, but attention is directed to the fact that under ordinary con- 
ditions Agaricus cumpestris does not give a copious growth when 
nitrogen is furnished from an inorganic salt and carbon in the form 
of the well-known sugars. Calcium hippurate in a solution of the 
necessary salts has almost invariably given better growth than other 
organic salts and carbohydrates. In general, casein has been a better 
source of carbon, or of carbon and nitrogen, than other proteids. 

When the manure is of good quality it furnishes, in pure cultures, 
a source of necessary nutrients, whether fresh or fermented, whether 
as a decoction or an infusion (a cold aqueous extract). 

Acid and alkaline media. — Manure which has undergone fermenta- 
tion for a few weeks is usually slightly acid in reaction. Under 
certain conditions of fermentation the acidity is increased, and this 
is probably an important factor in making the manure from animals 
fed with green foods less valuable for mushroom work. Some acid 
tests were made of beds which had failed to yield satisfactory results, 
and in many instances it was found that the acid content was much 
above the normal. A small series of experiments was therefore 
instituted to determine the relative amount of acidity or of alkalinity 
most favorable for the growth of the spawn under pure-culture con- 
ditions. In this test there were also included several other edible 
fungi, the results of all of which are included in the table below. 
These experiments were made in large test tubes, and in such a test 
it was impracticable to determine absolute acidity or alkalinity, and 
from the results only a rough qualitative comparison could be antici- 
pated. . Potassium hydrate and lactic acid were used as reagents. 
The. duration of the experiments was one month, and duplicate cul- 
tures were used in every instance. 

Although the results are not wholly uniform, it may be inferred 
that in the case of Agaricus cainpestns a marked acidity of the 
medium would be unfortunate; ('a? ratio cyathiforme, on the other 
hand, seems to have grown somewhat better, in general, in the more 
acid media; Coprinus comatus grows under a wider range of condi- 
tions; and Coprinus atramentarius, in this instance, thrives in an 
alkaline medium. Further tests on a quantitative basis are required 
before definite conclusions may be drawn. This matter will also 
receive further attention when facilities are at hand for undertaking 
to better advantage than has yet been possible the practical growing 
of the other species, besides Agaricus campestris, included in this test. 



TEMPERATURE AND MOISTUBE. 



31 



Tap.le VII. — Result* of tests nf acidity and alkalinity. 



Nature of 
Medium. stable Agark . us 

compost. | campestris . 



Extent of growth. 



Calvatia cya- Coprinusco- Coprinusatra- 
thiforme. matus. mentarius. 



{Fresh ... 
Rotted.. 

IFresh . . . 
:> drops KHO I 

I Rotted . . 

IdropKHO fe d - : ; 

I Fresh . . . 



Very slight 
Slight 



Very slight . 
...do 



Control . 



1 drop acid. 



1 Rotted. 

{Fresh .. 
Rotted . 



f*ov S »aa -!{»::: i:::^: 



1 good, 1 

fair. 
Very good . 

Good 

Very good . 
1 very good, 

1 fair. 
Very slight 

1 contami- 
nated. 1 
very good 

Very slight 



1 none, 1 
slight. 

None 

Very slight . . 

None 

1 good. 1 none 

Contain i n a - 

ted. 
1 slight, 1 

good. 

Very slight . . 
... .do 

Very good . - . 



Slight 

Very slight . 

1 very good, 1 

excellent. 
Very good . . . 

Excellent 

do 

do 

None 

Excellent 



....do. 
...do. 
None.. 



1 good, 1 very 
slight. 

Contamina- 
ted. 

Very slight. 

Good 

Very good. 
Excellent. 

Very slight. 

None. 
Very slight. 



Do. 
Do 
Do 



TEMPERATURE AND MOISTURE. 

The temperature factor is, next to that of good spawn, perhaps the 
most important in mushroom growing. It has been frequently 
stated that mushroom growing is not profitable when the temperature 
may not be maintained more or less continuously at from 50° to C>0° F. 
It is very probable that the exact temperature which may be con- 
sidered an optimum will vary somewhat m different sections of 
the country. It will be noted later in detail that the temperature 
factor acts not so directly upon the growth of the spawn or the produc- 
tion of mushrooms as indirectly to render some other conditions of the 
environment injurious. It is best to consider that in practice the op- 
timum temperature for mushroom growing varies from .">:'> : to 58° F. 

"When the matter of temperature was first under consideration, 
a series of pure cultures of Agaricus campestris was placed at 
different temperatures in the laboratory in order to determine the 
rapidity of growth. It was soon found that a temperature above 
C>0° F. and, indeed, as high as from 80° to 85° F., was much more 
favorable to rapid growth than a lower temperature, provided, 
of course, that the higher temperature did not encourage a too 
rapid drying out of the culture. It was soon definitely ascer- 
tained that the conditions of pure-culture growth are essentially 
different from those attending the growth of mushroom spawn in 
the bed. This was perhaps best indicated by comparing spawn 
grown in pots at 85° F. under impure conditions with similar 
spawn grown at 50° F. At the former temperature, even though 
the conditions of moisture were properly maintained, there was 
little or no growth. Foreign fungi, molds, and bacteria, as well 
as insects, were, however, abundant. At the lower temperature there 
was little or no evident appearance of other fungi, molds, or insects; 
6329— No. 85 — 05 m 3 



32 MUSHROOM GROWING AND SPAWN MAKING. 

yet the mushroom spawn grows slowly and continuously so long as 
oilier conditions are maintained. From numerous experiments of 
this nature it is apparent that the temperature relation is one which 
is governed by the competition to which the mushroom spawn is sub- 
ject in the bed. This is, of course, wholly in accord with the results 
obtained from the study of the relative growth made by mushroom 
spawn in fresh and composted manures. 

The statement previously made, therefore, that the optimum tem- 
perature may vary slightly in different localities is true on account of 
the fact that the mites, insects, and other animal pests of mushroom 
growing may vary considerably in different localities, or under dif- 
ferent conditions, even though there may not be .a great variation, 
perhaps, in the bacterial and fungus flora of the compost upon 
which the mushrooms are grown. Certain insects, for example, are 
more abundant in a moist climate, but if special precautions can be 
taken to eliminate all such pests, the growth problem is confined to 
the interrelation existing between the mushroom spawn and the 
microscopic Mora of the compost. Mushrooms grown in the open 
will probably show greater variation with reference to the tem- 
perature factor than those grown in caves or cellars. 

While a number of interesting problems would be presented by a 
study of the interrelation of the mushroom mycelium with that of 
other microscopic fungi present in the compost, these are matters of 
detail; and it has been wholly impossible thus far to give any atten- 
tion to suggestions which have been furnished by the experimental 
data. It may be possible that other species of mushrooms are more 
independent of insects and other microscopic fungi, and such fungi 
may therefore be more suitable for cultivation at high temperatures 
than is Agaricus campestris or any of its close allies. A considerable 
effort is being made to obtain spawn of certain species of Agaricus, 
and also of other edible mushrooms which make their appearance 
during the warm weather. At this time, however, it is not possible 
to say what results of value may be anticipated from this line of 
work. 

The direct effect of a temperature above the optimum upon the spo- 
rophores is manifest through lengthening of the stipes and rapid 
expansion of the caps, ordinarily accompanied by toughness and 
decreased size. In other words, the lower grade market product is 
produced at the higher temperature. 

The moisture factor is also one of importance. It is undesirable 
that the place in which mushrooms are grown should be very damp, 
or dripping with water. Nevertheless, a fairly moist condition of 
the atmosphere should be maintained throughout the growing and 
productive period. There should be a gradual but slight evaporation 
from the surface of the beds, and sufficient ventilation to insure this 



PREPARATION OF THE COMPOST. 33 

is believed to be essential. It is certain that in poorly ventilated 
caves mushrooms do not succeed. On the other hand, in a dry 
atmosphere, or exposed to drying winds, mushroom beds soon cease 
to hear, while such sporophores as are developing may have their 
caps cracked and torn. 

Mushrooms are grown in cellars, caves, or specially constructed 
houses largely on account of the fact that temperature and moisture 
are then practically under control. The nature of the structure or 
cellar which is constructed for mushroom growing must be deter- 
mined, therefore, not merely by its expense, but by the effectiveness 
of the structure in regulating the factors indicated under the par- 
ticular climatic conditions. 

It is not possible at this time to discuss cellar or house construc- 
tion, and the accompanying illustration of mushroom houses (Plate 
VI. fig. 1) must suffice to give an idea of the types which are in use. 

PREPARATION OF THE COMPOST. 

It is not to he understood that there is one and only one method of 
preparing compost for mushroom growing. Nor is it always neces- 
sary that the compost shall he in one particular stage of fermenta- 
tion or decay. In fact, every change of condition elsewhere may 
necessitate a similar change in the amount of fermentation which 
may be most desirable. At the outset it should he understood that 
it is not the "fermentation" which is absolutely essential." The 



o Repin, 1. c. I See translation in The Garden (London}, February 5, 1898. 
Special reprint, pp. 10-16.) Here it is stated thai "manure is rendered capa- 
ble of Supplying nutriment suitable for niushi ins only by means of fermenta- 
tion ; " further, that "all the higher orders of mushrooms, the spores of which 
I have succeeded in causing to germinate, have a sterile spawn of a similar 
nature." Again, the conclusion is expressed somewhat indefinitely that manure 
is "rendered suitable" by means of chemical combustion, which is said to 
proceed rapidly only at a temperature above ITS" V. : that it is not the soluble 
substances in the manure which are valuable, but rather the cellulose matter. 
together with the necessary salts. 

In this connection it is of interesl to note that the material constituting many 
of the beds in the experimental cellar at Columbia. Mo., were fermented at 
comparatively low temperatures. A complete temperature record was kept of 
18 small compost piles in which special kinds of manure were prepared, 
and in only one instance was the temperature in any pile more than 140° F. 
In some cases 120° I". was the maximum attained. 

Repin implies that mushrooms will not grow in manure until there has been 
effected "the destruction of all the soluble organic matters, which disappear 
through the agency of bacteria or are consumed in the process of oxidation." 
Very simple nutrition experiments clearly demonstrate that these conclusions 
are erroneous. 

It may be stated, however, that peculiarities appear when the fresh manure 
contains certain compounds which render it injurious: for example, the my- 
celium does not grow readily in pure culture upon fresh manure from animals 
fed almost wholly on green forage. Such manure is improved by fermentation. 



34 MUSHROOM GROWING A.Mi SPAWN MAKING. 

L ' fermentation " is of itself a minor matter. In pure cultures, where 
sterile media are employed, mushroom spawn starts slowly, but 
linally grows best, in general, upon fresh (wholly unfermented) 
manure. It grows least well, or, rather, less densely, so far as tested, 
on very well fermented manure. This certainly indicates that it is 
not fermentation which is ordinarily advantageous. In practical 
mushroom growing, however, it is not possible to deal with pure cul- 
tures; and, therefore, other conditions of the environment must bfe 
correspondingly changed. The rapid oxidation action of bacteria, 
and perhaps of independent ferments, upon manure causes a consid- 
erable rise of temperature. At the higher temperatures (which 
may be maintained as long as there are present rapidly oxidizable 
food products) bacterial action is vigorous, and is unquestionably 
injurious to mycelial development. Wholly aside from the rise of 
temperature accompanying their activities, bacteria are otherwise 
injurious. In fact, manure which is put to ferment in a small test 
lube shows little or no rise of temperature above that of the place in 
which it is incubated. Nevertheless, the mycelium of the mush- 
room will not grow under such conditions. Rapid bacterial action 
is therefore prejudicial. Under those conditions where bacterial 
action is not rapid, fresh manure might be used to advantage; in 
other words, if the beds are so constructed that the manure ferments 
very gradually, without either excessive bacterial action or rise of tem- 
perature, then spawning might lie made in fresh manure. 

The old belief that rotten manure does not have the necessary 
strength — that is, does not produce so vigorous a mushroom growth 
as that which has been less transformed by bacterial action — has been 
confirmed by practical experiments. This loss of effectiveness is 
probably due, in part, to a change in texture or to other physical 
changes. In well-rotted manure there is ample food material to sup- 
port a very good growth of mycelium in pure cultures. This has 
been chemically proved by sterilizing such manure and growing mush- 
room spawn upon it in pure culture. Nevertheless, by comparing 
(in Table VIII) No. 12 with Nos. 13, 14, and 15, it will be seen that 
beds prepared with well-fermented manure and left for some tini" 
before spawning do not yield so well. It is believed (hat here the 
physical condition has much to do with the result. 

The hitler does not by any means invalidate (he following practice, 
which has commended itself to some very successful growers: The 
manure is piled in very large compost heaps, where it is kept moist 
and is turned only once or twice. It ferments very slowly. Then it 
is carted into the cave, or mushroom house, long before it could be 
considered in proper condition to be spawned. The beds (usually 
Hat when this is the procedure) are made immediately. These are 
fairly well moistened and compressed, then left to undergo a gradual 



PREPARATION OF T 1 1 !■' COMPOST. .">. r > 

fermentation, which may require a month. When the manure shows 
a tendency to fall to the temperature of the room il is spawned. 
Meanwhile, it will doubtless be found that a heavy crop of some 
small species of Coprinus wil] have appeared. The presence of this 
fungus is not injurious, hut rather it may be taken as an indication 
that the conditions are favorable. 

Ordinarily the manure is obtained as fresh as possible. It should 
include the straw used in bedding the animals, and the quality of the 
straw will determine to some extent the value of the manure. The 
straw of cereals is far better than that of most other grasses. The 
more resistant straws seem greatly to improve the texture of the com- 
post for mushroom purposes. Commercially il is a mistake to 
attempt to get the manure free from straw. If fresh manure is not 
obtainable, that which has been trampled by the animals is ordinarily 
rich, well preserved, and desirable. It ferments best in large piles, 
and these may be of considerable extent, about 3 or 4 feet deep 
throughout. If not uniformly moist the material should be sprink- 
led. At no time is a very heavy watering desirable. In from four 
days to a week or more the compost should be turned, or forked over, 
and a second turning will be required a week or ten days later. 
Water should be added only when necessary to maintain a moist (but 
not a wet) condition. With this amount of moisture, and with the 
piles deep enough to become fairly compact as a result of their own 
weight, there will be little danger of any injurious fermentation. 
During the normal fermentation the temperature may rise higher 
than 150° F. In from fifteen to twenty-one days or more, depending 
upon the conditions, the temperature will begin to fall, and the com- 
post may be used in the construction of the beds. When used in the 
beds, it has ordinarily lost all objectionable odor, and the color of the 
straw has changed from yellow to brown. In figure 2 on Plate V 
is shown a shed in which the manure is composted during the summer. 

As stated in Farmers' Bulletin No. -J04 : 

It is the custom witli sonic growers to mix a small quantity of loam, about 
one-fourth, with the manure. This enables one to use the manure earlier; and. 
indeed, under such circumstances it may sometimes lie used with but little or no 
composting. Nevertheless, the majority of growers have obtained greater suc- 
cess by the use of the manure alone, and this is also the writer's experience. 
Very well-rotted compost should not lie used in mushroom growing if large and 
solid mushrooms an 1 desired. When sawdust or shavings are employed for 
bedding the animals, the composting may require a somewhat longer period. 

It has been the experience of some of the most successful growers 
that the use of shavings for bedding material in the stables docs not 
injure the value of the product for mushroom work. The presence 
of a large amount of sawdust is, however, objectionable so far as the 
writer's experience goes. Compost containing much sawdust is 



36 MUSHROOM GBOWING AND SPAWN MAKING. 

necessarily very "short," and therefore the physical condition is not 
the most favorable 1'or Agaricus campestns. 

In another chapter attention is called to the fact that the value of 
the manure depends to a considerable extent upon the feed given the 
animals. It would not be wise to depend upon that obtained from 
stables in which hay and green foods are used to too great an exteni. 
Moreover, it is not believed that compost made from the manure of 
cattle barns is in mushroom growing as desirable as stable manure. 

In some cities the municipal ordinances require that the manure 
shall lie promptly removed from the feeding stables or that it shall 
be disinfected. In the latter case crude carbolic acid, or even corro- 
sive sublimate, may be used to secure this end. Manure thus disin- 
fected is, of course, undesirable for mushroom work. For the same 
reason the manure of veterinary hospitals is of questionable value. 

It is not wholly improbable that some other waste products of the 
farm, field, and forest may be utilized in mushroom growing; never- 
theless, no such product has yet been found which, under the condi- 
tions of the experiment, has yielded sufficiently to make it of special 
interest in growing Agaricus oampestris. Among the products which 
have been tested, either alone or in conjunction with some commer- 
cial fertilizer, are the following: Leaves of deciduous trees, needles of 
conifers, sawdust, cotton-seed hulls, cotton seed, corn stover, sorghum 
stover (or bagasse), rotten hay. sphagnum, and yeddo fiber. The 
writer is convinced that greater profit may be anticipated, for the 
present, at least, if the culture of Agaricus oampestris is confined to 
manure; and if other edible forms which grow in the woods are used 
in beds of leaves, etc., as indicated elsewhere in these pages, it is quite 
possible that such a fungus as Coprinus <<>iii(itin< may be grown suc- 
cessfully in this latter way. It may. however, be too much to hope 
that (he morel may also be thus made amenable to culture, although 
leaf mold is in nature the favorite habitat of this fungus. 

From the prompt and abundant growth of Agaricus oampestris on 
half-rotted leaf mold in pure cultures, it was thought that mushrooms 
might be grown to advantage upon this product. The practical 
experiments made to test this point are distinctly discouraging, as 
shown by reference to Xo. IT. Table VIII: Nos. •''> and 4. Table IX. 
and No. 11, Table X. 

For the most part manure may be composted in the open air. It 
may, however, be prepared with greater uniformity under cover. 
During midsummer, protection may be desirable on account of dry- 
ing out. while in the winter it is more important in case of excessive 
cold. If it is necessary (o compost manure during the winter, more- 
over-, the piles should lie of considerable depth. 



INSTALLATION OF BEDS. ^7 

INSTALLATION OF BEDS. 

In making the beds, as well as in other phases of mushroom work, 
regard must be had for all environmental conditions. The type of 
bed should be determined by convenience, and the size, to a cer- 
tain extent. by the temperature to which the beds may be exposed. 
The Hat bed, frequently referred to as the English type, is more 
commonly employed in the indoor work in England and America. 
With this type merely the entire floor space may be utilized, as illus- 
trated in the frontispiece, Plate I, or the beds may be arranged in 
tiers of shelves. In figure 1 on Plate V a view may be had of the 
supports for shelf beds in a large commercial house. In this house 
there is the greatest economy of space. The shelf system gives the 
greatest amount of bed space and is certainly most economical where 
the floor space is an important factor. Such beds do not require 
great depth, but merely sufficient to insure an ample development of 
spawn. They should be from 8 to 10 inches dee]) after being firmed 
or compressed. 

The ridge-bed system is employed almost exclusively in the caves 
about Paris. This system is also in use in open-air culture. It may 
be used to advantage in low cellars, caves, or houses when labor is 
not too expensive. Ridge beds increase slightly the surface area and 
permit of easy passage from one part of the cave to another. The 
size, of such beds in caves, or under other conditions where the tem- 
perature remains practically uniform, should be not more than '2 feet 
wide at the base and 15 inches high, tapering gradually to the top 
when compressed. Slanting beds are commonly employed next to 
the walls. Large beds are desirable under changeable open-air 
conditions. 

The prevalent opinion among amateurs that the bed should always 
be deep enough to maintain a considerable beat is believed to be erro- 
neous. Grown under more or less uniform conditions, mushrooms 
seem to require no bottom heat, and the bed should fall to the tem- 
perature of the room some time' after spawning. Bottom heat, and 
hence large beds. are. however, desirable when sudden changes of 
weather would so reduce (he temperature of the bed as to delay 
growth. Under similar conditions, as well as in dry air, mulching 
may be required. 

As previously stated by the writer in Farmers' Bulletin No. 204 
of the Department of Agriculture — 

In any ease, the manure is made up in the form of the bed desired and should 
be firmed, or compressed, to some extent immediately, in order to prevent dry- 
ing out and burning when the secondary fermentation takes place. At this time 
the manure should he neither wet nor dry. but merely moist. The only prac- 
tical test of the proper moisture content of the manure which can lie relied upon 
is when, upon compression, water can not readily be squeezed out of it. 



J5N MUSHROOM GROWING AND SPAWN MAKTNG. 

SPAWNING AND CASING THE BEDS. 

From what has been said concerning the temperature requirements, 
it will he evident that spawn should not be inserted in the beds until 
the temperature has fallen low enough to insure successful competi- 
tion on the part of the mycelium with other organisms. In many 
iirticles on mushroom growing it has been suggested that beds may be 
spawned when the temperature has fallen to about 90° F. From 
experience and observation, the writer can only conclude that such a 
temperature is frequently fatal, and it is believed that the tempera- 
ture of the beds should be permitted to fall to 70° F. before being 
spawned. In fact, the most successful results have been obtained at 
temperatures from 65° to 70° F. It was formerly believed that if 
the spawn were inserted at 90° F. this higher temperature incited the 
rather dormant mycelium to rapid and vigorous growth. It is clear, 
however, that the rapid development of new mycelium from the pieces 
of spawn brick inserted is not so important a factor as suitable 
conditions for continued growth. If the temperature falls rapidly 
from 90° F. after spawning, however, no injury may result. Never- 
theless, it is to be considered an unfortunate condition. 

The bricks of spawn may be broken into from ten to twelve pieces. 
from U to '2 inches square. These pieces may be inserted about 1 
inch beneath the surface of the manure. In flat beds they may be 
placed from 10 to 12 inches apart throughout the bed, and in ridge 
beds the pieces should be inserted on each side alternately, one near the 
top and the next near the bottom. It is well to insert the pieces 
vertically, as the mycelium does not then seem so readily to suffer 
damping off. After spawning, the beds should again be firmed, and 
they are then ready to lie cased or loanied whenever this process may 
seem most desirable. At the time of spawning the beds should be in 
the best condition possible for the growth of the mycelium. Delay 
in growth at this time is one of the surest indications of a light yield. 
If the bed contains the proper amount of moisture, and if the walls 
and floors of the house or cellar are sprinkled occasionally, so as to 
maintain a moist condition of the atmosphere, it is possible to avoid 
wholly the use of water upon the beds immediately after spawning. 
In no case should a bed recently spawned be heavily watered. The 
surface may be sprinkled, if there is a tendency toward drying out. 
The same test for moisture content as has been outlined previously 
in these pages in the chapter on preparing the manure should be 
followed. The beds should become gradually somewhat drier, how- 
ever, during the growth of the spawn. 

The absolute water content for the bed at the time of spawning 
should be about 40 per cent, although this will vary considerably, 
according to the conditions, and especially with relation to the 
quantity of straw in the manure. 



MUSHROOM GROWING. 39 

If the spawn grows rapidly at first and spreads throughout the bed, 
it will not be injured by a slight drying out, or by a temperature even 
as low as 32° F. On the other hand, a continuous high temperature 
•for several days, or excessive watering-, is sure to result in an irrep- 
arable injury. In several instances where the experimental beds of 
the writer have been made during the late autumn, and where a 
vigorous growth of spawn has been secured before the advent of the 
coldest weather, the beds have remained unproductive throughout the 
winter months, or so long as the temperature remained intermittently 
below 40° or 50° F. With warmer weather, these beds have come 
into bearing several months later, and where the temperature has then 
remained favorable for some time a good yield has been obtained. In 
this ease, moreover, the bed will bear much longer at a temperature 
of 60° F., or above, than if the temperature has been constantly in the 
neighborhood of (>0° F. throughout the growing season of the spawn. 
As a rule, beds thus tilled with spawn and then subjected for a time 
to cold conditions yield at the outset much larger mushrooms than 
beds exposed to a more constant temperature, even if this constant, 
temperature may be the optimum. 

At any rate, the beds must be " cased " as soon as convenient after 
the spawn is inserted. As a rule, one should wait from one to (wo 
weeks in order to lie sure that the spawn is growing. Casing consists 
in applying to the bed a layer of loam from 1 to 1.', inches deep. In 
France the casing soil consists usually of calcareous earth, sometimes 
mixed with loam. Ordinary loam of almost any quality will suffice. 
This should be secured in advance, anil it is well to protect it from the 
weather, so that at a convenient time it may be worked over and, if 
necessary, screened, in order to free it from large pebbles or trash. 
When the loam is applied, it should, on ridge beds, be carefully 
finned. When cased a bed should require watering for the most part 
merely to maintain a moist surface. 

MUSHROOM GROWING. 
EXPERIMENTS AT COLUMBIA, Mo. 

The practical experiments in mushroom growing which have been 
undertaken at Columbia. Mo., were designed, in the first place, to 
determine the exact effect of conditions upon the growth of mush- 
rooms, and in the second place to test or immediately apply the 
results obtained or suggested by the laboratory -work. The effects 
of temperature, moisture, etc., have already been discussed, and the 
conclusions drawn have been based upon the most careful observa- 
tions of the experimental beds, as well as upon the evidence which 
lias been obtained by a personal study of the conditions in commer- 
cial mushroom houses and caves both at home and abroad. It is 
needless to give in detail the record of all failures or of poor yields 






40 



MUSHROOM GROWING AND SPAWN MAKING. 



invariably obtained when the conditions were unfavorable — that is, 
when they were beyond the limits which have been more or less 
definitely stated as requisite. On the other hand, the results which 
are given do not represent the best yields obtained; they are those 
which seem to be most instructive. 

The experimental work has been seriously handicapped in one par- 
ticular. With only one set of experiments (those recorded in Table 
VIII) has it been possible to maintain a temperature constantly 
-between 50° and C>0° F. Unfortunately a north basement room 
which gave those results during the winter of 1903-4 has not since 
been available for the work. The results are, however, comparative 
when not absolute. 

The results given in Table VIII are referred to in various parts 
of this bulletin. Attention should be directed to the fact that many 
of these beds were yielding well when the experiment was neces- 
sarily closed to make room for a second series of experiments 
planned during the same winter. Beds Nos. 6, 9, 13, 25, and 40, for 
instance, each yielded between 8 and 15 ounces the day the experi- 
ment was closed, while beds Nos. 2, 10. 14. 23, 26, 30, and 37 each 
yielded 1 pound or more on the same day. 

It is to be noted that a considerable number of beds in this series 
produced more than 1 pound per square foot, and some nearly 
2 pounds for a similar area. It is certain that some beds would 
have yielded more than 2 pounds if they could have been per- 
mitted to produce longer. 

Table VI 1 1. — Yields <>f experimental mushroom beds. 



i 

X 

■"■a 

5 

u ® 

V 

9 

to 


Material u&ed in 

the bed. 


Source of the spawn. 


6 
u 

°1 

45 a 

ss 
u 

to 


-p 
a> 

<3 

en 
a 

is 

s 

Is 


T3 

g 

w 

03 • 
O >> 


+3 

eg - 

gi 
.ss. 

-- ■— 
$ o 

8* 


P. 

a> 

9 . 

P 
a 

(0 

H 


u 

a 

0. 

{0 . 

u o 

a o 

3" 

o ® 
u 

03 

s§ 

2 
"3 


i 

2 


Fermented 

horse manure. 

do..: 


Alaska, old 


27 

104 
51 


53 

20 


54 


1117 
20 





115 

85 

112 
102 
136 



5 


6 

6 
6 

6 
U 

(1 

5 

U 

B 

6 

6 
6 


18.0 
3.6 


3 

4 


do ... 

do 

do 


English, current year market 
product. 


7 


1.0 
0.0 


5 








0.0 


6 

7 
8 
9 


do.. 

do 

do 

do 


Alaska. U. S. Department of Agri- 
culture. 

Bohemia, U. S. Department of 
Agriculture. 

Mixed varieties, U. S. Department 
of Agriculture. 

Bohemia, U. S. Department of 
Agriculture, light spawning. 

Bohemia. U. S. Department of 
Agriculture, heavy spawning. 


51 
53 
51 
68 
46 


47 68 

48 17 
78 34 

102 
71 65 


18.8 
13.0 
18.6 
17.0 


10 
11 


do 

do 

Fermented 
horse manure 
(bed left for 2 
months before 
beingspawned) 


22.6 

0.0 


12 


Bohemia, U.S. Department of 
Agriculture. 


111 


5 




0.8 



MUSHROOM GROWING. 



41 



Table VIII. — Yields of experimental mushroom beds— Continued. 



P. 

a . 

B 

S 

s 



Material used in 
the bed. 



Source of the spawn. 






13 

14 
15 
16 

17 



in 



21 
88 

83 

34 
25 

26 



28 



411 



(3 



Fermented 
horse manure. 

|....do 

Leaf mold 

do 



Fermented sta- 
ble manure: 
bed fairlycom- 
pact. 

Fermented sta- 
ble manure. 
do 



Bohemia, U. S. 
Agriculture. 

— .do 



Department of 



Calvatia cyathiforme 

Bohemia, U. S. Department of 
Agriculture. 

Alaska, U. S. Department of Agri- 
culture. 



.do. 



.do. 

do. 

.do. 
.do. 
.do. 

.do. 

.do. 

.do. 



do 

Fermeuted sta- 
ble manure and 
5 pounds cot- 
t m-seed meal. 
Fermented sta- 
ble manure. 

do 

do 

do 

do 

Fermented sta-^ 
ble manure and 
cotton-seed 
hulls. 
Fermented sta- i 
ble manure: 
bed heavily 
compressed. 

do 



Bohemia. U. S. Department of 

Agriculture. 
Var.?, U. S. Department of Agri- 
culture. 
American commercial more than 

1 year old. 
American commercial, Bohemia. . . 

do 

Bohemia, U. S. Department of 

Agriculture. Loose cakes: dried. 
Bohemia, U. S. Department of 

Agriculture. Watered freely 

late. 
Bohemia, LT. S. Department of 

Agriculture. Watered freely. 
Bohemia, LT. S. Department' of 

Agriculture. 

do .__ 

do.... 



English commercial, St. Louis 

English commercial. New York . . . 
Bohemia, Americal commercial . . . 
Alaska, American commercial. .... 

French, commercial flake 

Bohemia, U. S. Department of 
Agriculture. 



.do. 



Fermented sta- 
ble manure and 
sphagnum. 

Fermented 
sheep manure. 

Fermented sta- 
ble manure, 

cotton-s I 

hulls, and cot- 
ton-seed meal. 

Fermented cot- 
ton-seed hulls ' 
and cotton- 
seed meal. 

Manure mold. 



Var.?, U. S. Department of Agri- 
culture. . 
....do.. 



do 
.do 



Bohemia, U. S. 
Agriculture 

....do 



Department of 



i Sod. Calvatia cyathiforme. Pure cul- 

tures. 
45 Old compost, left il Bohemia, 17 . S. Department of 
2 months be- 1 Agriculture, 
fore spawning. 



S ■" 



Ill) 
241 



93 

11)1 
96 



42 
46 



TO 
,1) 



.VI 

til . 

4li 
46 

50 

46 

55 



96 






111 

46 
22 


53 

67 
50 


Hit 
113 

T2 


T4 


75 


159 


42 


51 


93 


m 


31) 


119 


90 

129 


55 
146 


145 
275 




102 
111! 


143 



1114 

1114 
22 

44 

57 



-J o 
B O 



.Sb. 
- s 


a 

03 

< 


3 — 
O 

5 

3 3 
"■ & 

% 


Ml 


fi 


27.7 


881 


12 


23.4 







ti 


0.0 

0.0 


189 


9 


21.0 


123 


6 


20.5 


14(1 


6 


23.3 


133 


B 


22.2 


II 


6 


0.0 



20.5 
15. 2 

12.11 

26.6 



15.5 
19. 8 



IS. 1 
30.5 



6 0.0 



0.0 

17.0 
16.7 
n.ii 
15.9 



17.3 
3.7 



7.3 
7.1 



6 

6 0.0 
0.6 



42 



MUSHROOM GROWING A.ND SPAWN MAKING 



The scries of experiments outlined in Table IX followed directly 
upon the series given in Table VIII. The beds in the first series 
were made in midwinter, and as the manure had been well fermented 
there was little or no rise of temperature after the beds were made. 
The spawn was therefore inserted at an unusually low temperature. 
During thaws in the late winter there was considerable seepage 
through the walls of the room. Some of the wall beds — Nos. 14 to 
•21 — were seriously damaged, but although beds Nos. 7 to 13 were 
also wall beds seepage was not evident in this region. Within about 
thirty days after vigorous mushroom production began in this series 
the basement was flooded, and the work was therefore brought to an 
abrupt close. The yield up to that time is given, however, since in 
this series there are included many fertilizer tests. 

Taiile IX. — Yields of experimental mushroom beds in a nonth basement room. 

1904. 



D"0 

■° 3 

d a. 



8 

9 
in 
11 
12 
13 
14" 
15a 
L6a 
17" 
is-. 
1H» 
20a 

:;i" 

22 
83 



25 
26 

27 
28 
29 
30 
31 

m 

33 



Bedding material and fertilizer. 



Spawn used. 



Stable manure and cotton-seed 
hulls. 

do 

Leaf mold and stable manure do 

do - do . 

Stable manure and sphagnum. do . 

Stable manure and cotton-seed ; do. 

meal. 

do ; do. 

Stable manure, timothy fed do . 

do -do . 

Stable manure, clover fed do . 

do do. 

do 
do. 
do. 
do . 
do- 
do, 
do- 
do. 
do. 

do 

do. 
do. 



Bohemia. U. S. 
Agriculture, 
do 



Department of 



Stable manure, bran fed. .*. 

....do 

Stable manure, corn fed 

do 

Stable manure, oats fed 

--..do 

Stable manure 

...do 

...do 

....do 

...do 

Stable manure and complete fer- 
tilizer: KC1, 1 ounce; KNO ; . 1 
ounce: bone meal, 7 ounces. 

stable manure ami incomplete fer- ...do. 
tilizer: NuNo :; , 1 ounce; bone 
meal, 7 ounces. 

Stable manure and NaCl, 8 ounces. do 

Stable manure and NaN< > a , 2< unices do 

Stable manure and 3IgS0 4 , 2ouuces do 

Stable manure and &LgS04,2ounces do 



Stable manure and kainit, 4 ounces 
Stable manure and Cat'l-., 2 ounces 
Stable manure and Na-fiPO,, 2 

ounces. 
Stable manure and (NH^jSu,, 2 

ounces. 
Stable manure and NaNO;;, 1 ounce; 

kainit, 2 ounces. 



.do. 
.do. 
.do. 



.do 



u a 



:« 



36 

4 
64 

73 

2 



1 

3 

84 

109 

12 

8 

3 

14 i 
24 
40 
17 
95 
61 
55 



« Some of the beds in this block— Nos. 14-21 —were seriously injured by seepage water, and the 
results are untrustworthy. 



MUSHROOM GROWING. 



43 



Table IX. — Yields of experimental mushroom beds in a north basement room. 

1904 — Continued. 






35 

36 

37 

lis 
39 

411 

41 
42 

43 

44 
16 
16 

4T 
4S 



Bedding material and fertilizer 



Spawn used 



Stable nianure_ 
.do. 






Stable manure, lime dressing 

Stable manure, ammonium molyb- 
date, i ounce. 

Stable manure, ZnNO,, 1 gram 

Stable manure 

do 



English commercial (ordered as 

fresh i 

Spawn from bed in full bearing lit; 

Bohemia, U. S. Department of 68 

Agriculture. 



.do. 



64 



.do. 
.do. 

do 

.do. 
.do. 



114 



Stable manure and sawdust . 



Stable manure 
...do 



A>j">ii a. < amygdcUinus . 

Bohemia, U. S. Department of 

Agriculture. 
English commercial i New York i . 
Bohemia. U. S. Department of 

Agriculture. 

Spawn from old bearing bed 

Pteurotus ostreatus 

English commercial (Philadelphia) 
Bohemia, U. S. Department of 

Agriculture. 

Var.y. American commercial 48 

Alaska. American commercial ... 64 



34 



(?) 
(?) 






4 
33 


6 

H 






o 


6 

6 


60 
22 


6 



From the experiments given in the foregoing- table further proof 
is furnished of the fact that stable manure alone, when of good 
quality, is sufficient for the growth of mushrooms. The addition 
of nutrient salts as fertilizers has not, on an average, given any 
marked increase in yield, but rather the contrary. It is hardly 
possible that the quantity of salts used on the beds was too little to 
make the effect felt. On the other hand, it was not sufficient to be 
injurious. It is evident from the experiment in bed No. -2 ( .>. for in- 
stance, that the addition of 4 ounces of kainit could not have been 
injurious. In some instances the results obtained by the use of fer- 
tilizers were poorer than where the manure alone was used. This, 
however, the writer believes to be due largely to differences in the 
spawn used, or the differences in condition owing to the location of 
the bed. for subsequent experiments with some of the salts winch 
seemed to be either injurious or beneficial have not wholly confirmed 
these results. It is to be noted, however, from the experiment in bed 
~Sn.it of this scries and also from bed Nb.30,in Table VIII, that the 
beds treated with cotton-seed meal have invariably yielded somewhat 
above the average. These beds do not come into bearing quite so rap- 
idly as those in which manure alone is used. It is thought that this is 
due to the fact that bacterial action is- at the beginning more rapid in 
beds containing cotton-seed meal, and that, consequently, when this 
wave of bacterial growth has passed the nutrition of the spawn is 
favorably affected. Experiments had already indicated that manure 



44 



MUSHROOM GROWING AND SPAWN MAKING. 



from animals which wore fed a poor diet, such, for instance, as 
grass or hay alone, is much less valuable than where the animals are 
well fed. The experiments in beds Nos. 10 to 22 were designed to 
test the value of some different feeds. The writer was fortunate in 
being able to secure manure from work animals which were being 
used in feeding tests where very different fowls were employed. 
Unfortunately, however, the mushroom beds were located next to a 
basement wall, and in beds Nos. 14 to -!1 the results were vitiated by 
the fact that there was considerable seepage water in that region 
during the thaws and heavy rains of the spring. Nevertheless, it is 
believed that the experiments in beds Nos. 8 to L3 are trustworthy. 
An attempt was made to check these results by using some of this 
manure in tube cultures, and it was found that the manure used in 
beds Nos. 8. !>, 10, and 11 particularly was unfavorable for the 
growth of the mycelium even in the pure cultures. 

On account of its stimulating action upon the spores of Agaricus 
eampestris a small quantity of ammonium molybdate was applied 
to one bed, No. 37, in order to test its effect upon the growing 
mycelium. Moreover, since certain salts of zinc at considerable dilu- 
tion have been found to increase greatly the quantity of mycelium 
produced by other fungi, zinc nitrate was employed in an adjacent 
experiment. The results of these two tests were the same. There 
was a profuse mycelial development and an abundant production of 
small deformed sporophores. 

Table N also summarizes a series of some interest. These beds were 
spawned early in November, 1!>04. Soon after the spawn began to 
spread throughout the beds — about December 15 — the temperature 
of the room fell to 40° F. From that time on until March 1, 1905, 
the temperature was constantly below 52°, and on several occasions 
as low as 32° F. After two or three weeks of warmer weather the 
beds began to bear vigorously, and the mushrooms, particularly the 
first ones, were of unusual size and of excellent flavor. Numerous 
individuals weighed from 6 to 8 ounces immediately after the sepa- 
ration of the ring, and a few mature specimens ranged from 10 to 14 
ounces. 



MUSHROOM GROWING. 45 

Table X. — Yields of experimental mushroom beds — Third serifs. 



Bed 

No. 


Material constituting bed. 


Spawn used. 


Compar- 
ative 

yield per 
lied, in 

miners 


1 
:.' 

3 

4 

5 

6 
7 
8 

11 

10 

H 

13 

H 

15 




English commercial, 2 vears old. 

Columbia, "green" spawn. U. S. De- 
partment of Agriculture. 

Poor grade English commercial, re- 
cent importation. 

Oood grade English commercial, re- 
cent importation. 

Good grade English commercial, H 
months old. 





do 


Til 


.do 


16 


do 


49 


...do 


411 


.. do 




. .do 


do 


34 


...do 


do 


54 


...do 


U. S. Department of Agriculture 1 > 
lumbia. 
do 


.Mi 




31 




.. do... 


30 




do 


3 




do 


6 




American commercial, probably . 1 . a r- 
vensis, var. 


60 


...do 


lis 









In some publications on mushroom growing the claim is made that 
did or practically exhausted beds may be brought into bearing again 
by heavy fertilization with liquid manure or with a weak solution of 
potassium nitrate. From a commercial point of view, no measurable 
success has resulted from any trials of this nature madeby the writer ; 
consequently, it is believed that exhausted beds should be immediately 
discarded. From the standpoint of mushroom sanitation, this is 
also particularly desirable. 

VARIABILITY IX MUSHROOMS GROWN UNDER DIFFERENT CONDITIONS. 

The writer does not intend to discuss even in a general way the 
relationships of the various forms of Agaricus — that is, those that 
may be considered allies of .1. campestris — which he has cultivated or 
studied in the field. Some reference to the variability of common 
forms should, however, lie made. For a comprehensive study of spe- 
cies and varieties, a knowledge of European forms as well as of those 
found in America is essential. Authors differ so widely in their 
descriptions of species, as well as in their conceptions of them, per- 
haps, that in the absence of unlimited material nothing short of con- 
fusion results from any attempt to harmonize opinions. It is suffi- 
ciently difficult to separate what many would regard as varieties of 
.1. co an pest ris from those of .1. arvensis. When specific rank is 
bestowed also upon such forms as .1. pratensis, A. vUlaticus, A. may- 
itificiis, A. rod 7» ani, etc., the difficulties are greatly increased. The 
writer has grown many forms of Agaricus, and, as might be expected, 
there seems to be no form which will remain practically constant 
under variable conditions. Besides general size, size of spores, etc., 



46 MUSHROOM GROWING AND SPAWN MAKTNG. 

some of the characters used in separating the common forms are color 
of gills; character of ring, particularly as to whether single or double; 
shape of stipe; color and markings of pileus; color of flesh, etc. In 
following the development of these characters in different forms, 
many variations will be found. Agaricus campestris grown on com- 
posted leaves shows very little pink in the gills. The color changes 
rapidly from dull pinkish-brown, or almost white, to a leaden hue. 
Several brown-capped forms, usually considered varieties of A. cam- 
pestris, never show a bright-pink surface unless produced under 
exceptionally favorable conditions, moist air being a sine qua non. 
The ring is naturally variable. In any variety of .1. campestris it is 
not uncommon for an edge of the partial veil to remain attached to 
the base of the stem as a volvate line, or this line may be left at any 
stauc during the elongation of the stem. Again, if the lower margin 
of the partial veil on the stipe separates slightly from the stipe, and 
upon drying curves slightly upward, there is an indication of a double 
ring. A very good double ring appeared on a number of very vig- 
orous specimens of an undoubted variety of .1. campestris during the 
present season. It is possible that there is a greater tendency to pro- 
duce a double ring when conditions are favorable for the production 
of the most vigorous mushrooms. Agaricus arvensis is also very 
variable with respect to the formation of a double ring, as also in the 
persistence of the partial veil. 

The shape of the stipe is in many forms dependent upon the con- 
ditions. Under favorable conditions a brown variety of .1. cam- 
pestris may have a very short, thickened, equal stem, when grown on 
manure, and practically uniform at maturity, while the same form 
grown on decayed leaves may show in the main a stipe with thick- 
ened base, gradually tapering to the to]). The color of the cap is of 
undoubted value as a varietal or specific character, yet it must be 
remembered that whether the surface be smooth or rough, merely 
fibrillose, or broken into scales of definite form, may depend entirely 
upon whether produced in moist air or in dry air, subjected to 
drying after being wet, etc. The color of the flesh is also dependent, 
to a considerable extent, upon the conditions. A specimen grown in 
even fairly unfavorable conditions will show the flesh somewhat 
darkened, and on exposure the characteristic pink tint will not be 
even momentarily visible. In other words, a considerable range of 
variation must be anticipated, and in comparisons there should be 
stated very clearly the conditions under which the particular forms 
are produced. 

Till': CULTIVATION OF VARIOUS SPECIES OF Ml SHROOMS. 

Iii Table X are given the results of a single test with Agaricus 
arvensis, or what is supposedly a brown variety of this species, and 



MUSHROOM GROWING. 47 

also of a single experiment with A. villaticus. In both cases the 
yield was excellent. It is not well to draw definite conclusions 
from individual tests, but it is believed that both of these forms will 
yield profitably in general culture under conditions similar to those 
required for .1. campestris. Plate III, figure 2, indicates the size 
and compactness of the mature sporophore id' .1. oillaticus. More- 
over, both of the species above referred to are to be recommended 
for texture and flavor. Two forms of Agaricus fabaceus (see PI. 
Ill, fig. 1), both with amygdaline odor and flavor, have been tried 
in relatively few experiments. In no case has the yield been very 
good, and further experiments will be required before it will be pos- 
sible to state under what conditions these forms may be most suc- 
cessfully grown. At the .Missouri Botanical Garden Prof. William 
T release has for some lime grown successfully one of these varieties. 

Owing to the profuse and rapid growth of the mycelium of Copri- 
niin comatus in pure cultures, it was anticipated that it might easily 
be grown in beds. The few experiments thus far made indicate that 
in impure cultures (beds) of leaf mold the mycelium grows and 
spreads very slowly. Hot weather prevented the maturity of the 
tests, but no sporophores were produced during a considerable pe- 
riod. In similar experiments Lepiota rhdeodes and Tricholoma i><)'- 
goriatum were used. The former has given unsatisfactory results thus 
far, but the latter is promising. 

It is not yet time to report on the possibility of growing the better 
and larger species of puffballs and the morel. It has already been 
indicated that the mycelium of these fungi grows well in pure cul- 
tures. From the pure cultures it has also been demonstrated that 
spawn may be made, but it has not been determined under what con- 
ditions the fruit may lie produced. Figure 1 on Plate IV shows a 
young specimen of one of the puffballs, Calvatia multiformis, the 
spawn of which is produced with the least difficulty. 

COOPERATIVE EXPERIMENTS. 

During the winter of 11)02-3 a small quantity of experimental 
spawn made by the writer was sent out to mushroom growers for 
trial: in 1903—1 this spawn was made in large quantity, and trial 
packages were sent to more than 100 growers or interested persons. 
At that time Farmers' Bulletin No. 204 had not been issued, and the 
instructions which could be furnished inexperienced growers were 
inadequate. Nevertheless, an attempt was made to obtain reports 
from all persons receiving the experimental spawn, even from those 
who had applied for and received spawn when the season was too far 
advanced for successful work except in caves and cool cellars. A 
number of reports were received, but, as might be expected, fully -V) 
per cent of these indicated that the conditions under which the experi- 
6329— No, 85^05 m— — i 



48 MUSHROOM GROWING AND SPAWN MAKING. 

meats were made were wholly unsatisfactory, and that, therefore, no 
favorable results could be anticipated. Among those whose report- 
indicated that the conditions were favorable, or fairly favorable, only 
a small percentage reported failures, while four-fifths of those claim- 
ing success secured yields of more than one-half pound per square 
fool of l>ed space, many obtaining more than 1 pound per square 
foot. In two instances a yield of nearly 2 pounds to the square 
foot was reported. The frontispiece, Plate I. a bed in full hearing, 
and Plate VII, figure 1, showing the mushrooms as prepared for mar- 
ket, are photographs furnished by cooperating growers who are now 
also making spawn of pure-culture origin. It was suggested to 
growers who received the experimental spawn that a comparative test 
of the English or other commercial spawns with that received from 
the Department of Agriculture would be of interest. Comparative 
tests were made and reported by lo growers. In most cases the 
English spawn, obtained at random on the market, failed to grow. 
In only one case did (he English spawn prove better than the pure- 
culture product, and in this instance the spawn furnished by the 
Department when used was nearly one year old. 

Failures may always he anticipated when attempts are made to 
grow mushrooms under adverse conditions, and it must lie said that 
greater success was obtained from the cooperative work than could 
have been hoped for. considering the fact that many of the persons 
who sent in reports were wholly inexperienced and were practically 
unguidetl. 

During the present year experimental mushroom spawn has been 
sent to more than 200 interested persons, and this will doubtless be 
the last general distribution of this product by the Department of 
Agriculture. Representing the varieties of Agaricux cumpestris 
commonly grown, mushroom spawn of pure-culture origin is now an 
established market product. In order that the standard of the 
American spawn may he maintained, spawn makers, dealers, and 
growers should see to it that only the fresh, recently dried product 
is used. 

Nevertheless, it is hoped that this cooperative work may he carried 
forward, looking toward the development of better varieties or the 
bringing into culture and the testing of new species. 

CAVE FACILITIES IN THE UNITED STATES. 

Cave facilities in the United States are by no means so meager as 
has been supposed. There are in some sections caves from which 
rock for Portland cement has been mined. Some of these have been 
utilized for mushroom growing. There are also natural caves of 
great extent in many of the States of the Central "West — especially 



OPEN-AIR CULTURE. 49 

in Indiana, Missouri. Kentucky, and Arkansas — as well as in Vir- 
ginia." The difficulty is to obtain caves within a convenient distance 
from cities, for stable manure becomes expensive if it must be hauled 
many miles or transported long' distances by the carload. Again, 
caves should be easy of access, since after each crop every vestige of 
soil, manure, etc., of the preceding crop must be removed as a sani- 
tary precaution. This is especially necessary since there is much 
waste space in most natural caves, and it becomes a very difficult or 
expensive matter to fumigate. If the cave system is extensive, it 
must also be possible to give it thorough ventilation. Many natural 
caves are the courses of subterranean streams. The latter are by no 
means objectionable if there is no danger from overflow. In many 
caves the stream has long since found a new channel and the cave 
is dry. Seepage water, usually accompanied by continuous stalactite 
and stalagmite formation, is undesirable. In some of the Eastern 
States coalpits or coal mines may be important for mushroom pur- 
poses. Where the coal mine is not too deep, or where perfect venti- 
lation may be given, there is no reason why it is not entirely suitable 
for mushroom growing. 

OPEN-AIR CULTURE. 

In some sections of England and France open-air culture of mush- 
rooms in beds is practicable during the late autumn and winter 
months, in which case the productive period may extend into the 
spring. The difficulties in the way of open-air culture are not merely 
those of maintaining a more or less uniform temperature, but also 
of maintaining practically constant conditions of moisture. For 
these reasons it is necessary to mulch the beds heavily with clean 
straw. In some instances a light mulch of straw is permitted to 
remain even during the period of production, for a rapid drying out 
of the surface would lie hazardous or fatal. It is better, perhaps, 
to put the beds under some form of protection, such as an improvised 
cold frame. 

In regions where the climatic changes ire marked, open-air cul- 
ture is probably not to be recommended during any season for com- 
mercial purposes. It is probable that there are some areas in the 
United States in which open-air culture might be practiced with 
profit. It has seemed that certain sections of California might be 
favorable for this phase of the work. In the interest of experiments 

"The writer is indebted to Prof. C. F. Marbut for the information thai caves 
are to be expected in the Silurian limestone, which occurs particularly in the 
extension of the Shenandoah Valley, in the blueirrass region Of Kentucky, and 
in the Ozark region of Missouri and Arkansas: also in the Lower Carboniferous 
limestone, which extends into Indiana. Kentucky, Tennessee, and Missouri. 



• r )D MUSHROOM GROWING AND SPAWN MAKING. 

along this line the writer has made a special attempt to acquaint 
himself with the conditions in that section of the country. This has 
seemed particularly desirable, inasmuch as fresh mushrooms could 
not be shipped to the far West from sections in which they are at 
present grown in quantity. From the information obtained it is 
thought that successful open-air mushroom growing might be antici- 
pated in those sections where the average temperature is between 
48° and 55° F., provided there are relatively few days when the 
temperature falls as low as 32° F. At the same time, open-air* cul- 
ture can not lie recommended for those sections in which dry winds 
are prevalent. As a rule, during the wet or winter season the rain- 
fall is so light that heavy mulching would probably suffice to prevent 
injury from excessive wetting. Nevertheless, it seems apparent that 
even in regions most favorable for open-air culture some inexpensive 
partial protection against the changes of temperature due to direct 
sunlight, or against heavy rainfall, would he desirable. 

It was also ascertained that Agaricus campestris appears naturally 
in some quantity during the months of January and February, or 
longer, during the rainy season. This, however, is also true of other 
species of fleshy fungi. The large size of some of the specimens of 
Agaricus campestris and .1. arvensis found would seem to suggest 
that they were produced from an unusually vigorous mycelium. 
This may he the result of a condition analogous to that previously 
mentioned, where, on account of the low temperature of the atmos- 
phere, the spawn may develop slowly through a considerable period, 
and finally, under favorable conditions, sporophores of unusual size 
are produced. 

In the following table are given the monthly mean temperatures 
from several representative stations in California during the years 
1809 and 1900. From this table it will he seen that so far as the 
mean temperature is concerned Eureka and San Francisco would be 
especially favorable during a large portion of the year. Independ- 
ence and Red Bluff are likewise satisfactory, while San Luis Obispo, 
Santa Barbara, Los Angeles, and San Diego show a mean which is 
perhaps rather too high. The moisture of the atmosphere, the 
prevalence of hot winds, the variation in the daily temperature, and 
the number of hot or cold days must all he considered. From the 
data obtained, the general conclusion seems to he that the most favor- 
able regions are those where conditions correspond closely to those of 
Eureka and San Francisco. This, however, represents a large region, 
including a considerable portion of the San Joaquin and of the 
Sacramento valleys. In a few places experiments have already been 
undertaken to determine the possibilities for the development of this 
work, hut no definite recommendations can be made until the experi- 



OPEN-AIH CULTUBE. 



51 



mental evidence is at hand. Tt may be said, moreover, that some of 
the regions which seem to be too warm for open-air culture may be 
especially favorable during several months at a time for mushroom 
growing in ordinary cellars, or in very simply constructed mushroom 
houses. In those sections the winter and early spring months would 
doubtless give the most satisfactory conditions; and this period. 
fortunately, corresponds with the tourist season— a season when the 
market demands are greatest. It is also possible that with mulching 
and with simple protection, mushroom growing may be successful in 
some of the Eastern States. 

Table XI. — Menu monthly temperatures at points in California,, in driiriix 

Fahrenheit. 





Eureka. 


San Francisco. 


Sa-i Luis 
Obispo. 


Santa Barbara. 


















1899. 


1900. 


1899. 


1900. 


L899. 


1900. 


City. 
53.0 


P.H.S." 




11 .-, 


50 t 


53.0 


50.7 


54.2 


56. 2 


55.4 




44.4 


4S.I1 


51.0 


53. 6 


54. 4 


56. 2 


54.6 


58.0 




4S.II 
4S.2 


511.0 


52 2 

54. Ij 


55.2 
54.0 


54.11 
56. 4 


58.2 

54. 2 


55. 3 

57. 9 


57 4 




59. 3 


19 6 


54. 4 


52. fi 


57.11 


54.11 


61.6 


59. 4 


59. 4 




52.(1 


5i;. :; 


56. H 


57.6 


62. 4 


63. it 


(12. 6 


64.4 


July 


54.8 


56. 4 


55. '.I 


58. 2 


64.4 


64.2 


65. 5 


68. 1 




55. 9 


57.11 


58. :i 


59. 7 


04. II 


64.9 


66.9 


68.9 




54. 8 


56.6 


58. :.' 


63. :: 


65. 5 


64.4 


66. 1 


69.9 




.->:;. ii 


53.8 


59.3 


58. s 


59. 6 


62. s 


62. 6 


64.8 




.v, 9 


53. 3 


51!. S 


56.3 


57.4 


5'.i. 8 


59. 1 


64.7 




4S.II 


50.8 


49. li 


5ii.:; 


54.3 


55.6 


55.6 


58 4 


Year 


50.9 


53. 2 


54.9 


56.2 


58. 4 


60.2 


59. II 


62.3 



Month. 



Los Angeles. San Diego. Independence. Red Bluff. 



January — 
February . 

March 

April 

May 

June 

July ... 

August 

September 
I irtober 
November 
December . 

Year . 



1899. 



19110. 1899. 



62 



58 
58 
60 

57 
64 
117 
71 
68 
67 
64 
06 

60 



ill 



56.0 
53. 4 
56. 4 
58.0 
5S.II 
61.4 
65. 6 
65. S 
65.5 
62. 7 
61.0 
58.7 



60.2 



1900. 



57. I 
57.2 
59.1 
57. I 
60.6 
63 '.i 
67. 1 
65. 7 
65. 3 
62. 8 
63. 7 
59.7 



411.2 
411. 5 
511.5 
59. 4 
60.0 
74. 2 
80. t 
72.6 
74.11 
55. 4 
49.4 
43.-1 



61.6 58.9 



1900. 



46.6 
48.1 
54.: i 
52.11 
115. 8 
75.4 
79.4 
72.4 
63. 5 
58.8 
50. 4 
43.4 



51.6 
52. 2 
60. S 
63. 2 
77.9 
82.0 
73.8 

78.(1 

111 II 

54.4 

45. 5 



190(1. 



48.8 

51. 1 
58.6 

57 (1 
(17.0 
76.8 
82.6 
77.(1 
69.9 
60.0 
54 8 
45.4 



" Foothills or suburbs of Santa Barbara, at an elevation of 750 feet above the city. 

Occasionally one reads of successful natural cultures of mush- 
rooms: that is. the production of this plant in pastures, lawns, etc. 
under more or less natural conditions. At Columbia. Mo., the writer 
has made numerous attempts to spawn plats in pastures and lawns; 
but thus far failure has attended every attempt. The spawning has, 
moreover, been tried at every season of the year. It is believed that 
in the section of the country mentioned only exceptionally favorable 
seasons will permit any success in this phase of open-air culture. 



52 MUSHKOOM UBOWING AND SPAWN MAKING. 

MUSHROOM SPAWN MAKING. 

The mycelium of the cultivated mushroom has long been known 
commercially as "spawn." From early times it has been recognized 
that mushrooms may be grown from spawn, and it is quite certain 
thai in all attempts to propagate mushrooms spawn has been used 
for the purpose. 

In France, in England, and in other countries in which the mush- 
room has long been grown it is recognized that it is not profitable 
continually to take growing spawn from one bed to be preserved as 
" seedage " for the next crop. The common expression is that the. 
spawn "runs out" in about three years. There seem to be few or 
no definite experiments indicating the exact conditions under which 
the spawn in two or three years loses the power of vigorous mush- 
room production. Nevertheless, it is the almost unanimous opinion 
of all extensive "rowers that there is a marked diminution in the 
yield after several successive propagations from the spawn in the 
mushroom bed. This has seemed to be true in the writer's experi- 
ments, although it must be sajd that accidents to experiments under- 
taken have made it impossible to report at this time upon the nature 
of this running out. That deterioration does result is apparently a 
fact accepted by all scientific men who have given attention to mush- 
room growing. It is possible, however, that under certain conditions 
the spawn might be repeatedly propagated without loss of prolific- 
ness. It is not necessary to enter here into a discussion of possibili- 
ties or to attempt to explain why weakening might lie evident under 
ordinary conditions. 

.1 " c/iinirc" method. — For practical purposes it is necessary to 
renew the spawn and to secure, if possible, spawn which has not pre- 
viously weakened itself by the production of mushrooms — known as 
virgin spawn. Natural virgin spawn may lie found wherever " in 
nature" it has been possible for the spores to germinate and to pro- 
duce a mycelium. .Ordinarily such so-called "spontaneous" appear- 
ances of spawn may be anticipated in compost heaps, rich garden 
beds, pastures near the feeding places id' animals, etc. 

Many attempts have been made by practical growers to develop 
-pawn from spores, sowing the gill portions of mature mushrooms in 
specially constructed beds; but the results, so far as the writer is 
aware, have not been satisfactory. As a rule, therefore, growers 
have been compelled to rely wholly upon a virgin spawn which has 
been obtained by chance. It is said that in the vicinity of Paris 
some persons make a business of searching for this virgin spawn, 
which they sell to the growers at a high figure. It is claimed that 
they become so adept in detecting the differences in the character of 
growth, the quality of odors, etc., that they can distinguish not only 



MUSHROOM -SPAWN MAKING. 53 

Agaricus campestris, but also some of its varieties. In England 
much of the virgin spawn h;is been obtained from pastures. Where a 
"'spontaneous" growth of spawn is observed, trenches are dug, and 
these are tilled with good stable manure. The latter in time becomes 
penetrated, and it is highly prized for cultural purposes. As a rule, 
the virgin spawn is used in spawning beds, which, when well pene- 
trated, are torn down, and the whole bed used as flake spawn in 
spawning the general crop. Again, the virgin spawn may be used 
in spawning the brick, or cakes, this being the form in which English 
spawn is usually made. However adept persons may become in the 
identification of various varieties of spawn by odor, etc., this must 
be considered essentially a chance method. 

.1 "selective" method. — From what has been said it will be per- 
ceived that very little advancement could be made in the selection of 
desirable varieties of mushrooms, in varietal improvement and the 
like, so long as the chance method of securing spawn should prevail. 
The studies in the germination of mushroom spores previously re- 
ferred to were encouraged by the apparent necessity of beginning 
with spores from mushrooms of known qualities in order to effect 
improvement. In recent years the investigations of Costantin" upon 
spore germination have found application in a department of the 
Pasteur Institute. By a secret method, mycelium is grown from the 
-[Hires in pure cultures. These cultures, which are. of course, pure 
virgin spawn, are then offered for sale to the growers. This spawn 
doe-- not seem to have received deserved consideration on the part of 
the growers. The secret method of effecting spore germination re- 
ferred to by Repin '' has also been practically applied by one of the 
largest seed firms in Paris. In general, however. French growers 
have not profited so much by the new methods, perhaps partially on 
account of the fact that these methods are not known and partially 
because of the expense of the new virgin spawn. It is to be noted 
that these methods imply pure cultures to begin with. 

The successful germination studies with chemical stimulation men- 
tioned in this paper were soon overshadowed by the discovery of the 
ease of making tissue cultures. The use of the latter method has 
been the means of a sudden advancement in spawn making in this 
country during the past two years, for many practical men have 
been quick to see the advantages which it offers. 

Pure-culture precautions. — It has already been stated that the 
pure-culture method of making virgin spawn is not one which will 
prove successful in the hands of wholly inexperienced persons, or of 
those who are unwilling to spend time and use the utmost care in the 
manipulation of the cultures and the culture material. The use of 



o Costantin, J., loc. cit. '' Repin, < '., loc. cit. 



54 MUSHROOM GROWING AND SPAWN MAKING. 

pure-culture methods necessitates to a considerable extent a knowl- 
edge of the bacteria and molds which are everywhere present in the 
air and which are especially abundant wherever there are dusty or 
damp, moldy conditions. The principle of making pure cultures is 
briefly this: The materials, or media, and all the vessels employed 
must be sterilized, which implies being heated at a temperature suffi- 
cient to kill all germs present in the vessels or materials used. If 
the vessels used are test tubes or other pieces of glassware with small 
mouths, they should, previous to sterilization, be plugged with cotton 
batting. This cotton batting prevents, when carefully manipulated, 
the entrance of germs from the air, and therefore keeps the vessel 
or medium in a pure or sterile condition. If such a vessel is opened, 
this should be done in a room free from currents of air or falling 
dust particles; and, while open, tubes and other apparatus should be 
held in a more or less horizontal position, so that they will be less 
liable to contamination. It follows, of course, that the cotton plug, 
if removed, should not come in contact with any unsterilized sub- 
stances. If, now, a small quantity of the growing mycelium of a 
mushroom from a pure culture is transferred to such a sterilized 
tube, using for this transfer sterile needles, or scalpels, there will be 
little danger from foreign organisms, and the piece of mycelium 
inserted will therefore grow as a pure culture free from all other 
fungi or bacteria. 

The tissue-culture method. — In making pure cultures of mushrooms, 
large test tubes or wide-mouthed bottles may be used. These should 
be carefully cleaned, and. if possible, a sterilization should be given 
by means of dry heat as a preliminary precaution. In this event the 
tubes are plugged with cotton plugs and placed in a dry oven made 
for the purpose. They are heated to a temperature of about 150° C, 
and this temperature should be maintained for nearly an hour. 
Ordinarily, however, in rough work it is not essential to employ this 
preliminary sterilization. In either case the tubes are next partially 
filled (about two-thirds) with the manure, or half-decayed leaves, 
upon which it is desired to grow the virgin spawn. A plug is 
inserted in each tube, and the tubes are then sterilized in a steam 
boiler or under pressure. If sterilized under steam pressure, as in an 
autoclave, it is necessary to use about 15 pounds pressure and to allow 
the tubes to remain at this pressure for from fifteen minutes to half 
an hour. If the sterilization must be effected in a boiler or in an open 
water bath, it can only be done at 100° C-, of course; and it is then 
desirable to boil the tubes for at least one hour on each of two or three 
successive days. 

With the tubes thoroughly sterile, the next step is to make the 
cultures or inoculations. By the tissue-culture method it is implied 



MUSH HI HIM SPAWN MAKING. 55 

that the inoculations are made from pieces of the tissue of a living 
mushroom. It is at this stage that selection may be made. One 
should procure from a bed of mushrooms in full hearing a mushroom 
which represents the most desirable qualities that are to be found. 
Size, quality, and general prolihcness must all be considered, as well, 
also, as other characteristics in any special selections. One may de- 
sire, for instance, to select from a variety which yields throughout 
a long period — one which is resistant to higher temperatures, etc 
Having found the mushroom from which it is desired to propagate, 
plants as young as possible may he used, and those which show the 
veil still intact are especially desirable. With a scalpel, or a pair 
of forceps, which has been sterilized by passing the blade through a 
gas flame, or even the flame from an alcohol or ordinary lamp, small 
pieces of the internal tissue may he removed, and these pieces trans- 
ferred to the tiihes. without, of course, coining in contact with any 
object whatever which has not previously been sterilized. It is a 
good idea to wasli the mushroom first, so that no dust will be made. 
Tile plant may then be broken open longitudinally and bits of the 
internal tissue readily removed without fear of contamination when 
one becomes adept in this kind of manipulation. Immediately upon 
inoculation the cotton plug is replaced in the tube, and after all the 
lubes are inoculated they should lie put out of the dust, preferably in 
a situation where the temperature is about that of an ordinary living 
room. In the course of several days a slight growth may be evident 
from the tissue if the conditions have been perfectly sterile. In the 
course of a week or more the growth should become very evident, and 
in three weeks the moldlike development of mycelium should spread 
to practically all parts of the medium in the tube. The method of 
making pure cultures and the laboratory apparatus usually involved 
are shown ill Plate VI, figure ± 

When the tubes are thoroughly " run " the contents may be removed 
and used in spawning brick. The contents of a single tube may 
spawn several bricks when carefully employed. If no transfers are 
made of the growing mycelium from one lot of tubes to another, the 
writer has not found it at all impracticable or unfavorable to utilize 
this first lot of bricks later in spawning others. No further trans- 
fers, however, should be made from these bricks to others under any 
circumstances in spawn' making. As elsewhere indicated, such a con- 
tinuous transference is injurious to the vigor of the spawn and 
diminishes the quantity of mushrooms produced. 

The commercial process. — The essentials in spawn making are (1) 
a uniform, compact manure brick: (2) vigorous and well-selected 
virgin spawn to he used in inoculating the bricks, and (3) favorable 
conditions for the storage of the bricks during the growth of the 
spawn. 



5f> MUSHROOM GROWING AND SPAWN MAKING. 

It should be indicated that there is no one method of making brick 
spawn. The process may and will be varied by each spawn maker. 
Any skill or mechanical devices which will simplify or improve the 
process in any particular are to he recommended. 

The materials entering into the composition of the brick are fer- 
mented stable manure, cow manure, and sometimes a small quantity 
of well-selected loam. Perhaps the chief value of these different con- 
stituents is as follows: 

In the horse manure the mycelium grows most readily. The cow 
manure binds the materials together into compact brick. The loam, 
which is perhaps least essential, is supposed to prevent cracking or 
hardening of the surface, and therefore contributes to the appearance 
of the finished brick, at the same time tending to prevent rapid fer- 
mentation during growth. It also in some cases facilitates the uni- 
form spread of the mycelium. If fresh manure is used, the necessity 
of using loam is perhaps to be emphasized. 

In the experiments which have been made under the auspices of 
the Department of Agriculture these materials have been used singly 
and in various combinations, and it is beyond doubt that the relative 
proportions of these should be determined by the special conditions 
under which the spawn is made. Excellent results have been ob- 
tained by using a mixture of from two-thirds to three-fourths stable 
manure and the remainder cow manure. In this case the compost 
for the brick is subjected to fermentation previous to its use. When 
loam is employed it may be used in more or less equal proportion to 
the cow manure; and the quantity of stable manure should about 
equal that of the other two ingredients. If the straw present does 
not become sufficiently disintegrated during the preparation of the 
manure to enable one to make a smooth brick, it should be removed, 
in part at least. 

The dry bricks ordinarily measure about .VI by S] by 1} (to H) 
inches. They should therefore be molded of somewhat larger size, 
perhaps 6 by '•> by 2 inches, since there is considerable contraction 
during drying. The mold consists merely of an oak frame of four 
pieces strongly riveted together. It may also be profitably lined 
with thin steel plates. In molding the brick one of two methods 
may be followed: (1) The compost may be thoroughly wet or pud- 
dled ; then, with the mold upon a board of suitable width, the manure 
is compressed into it, the mold removed from the brick then formed, 
and the board pushed along for a succession of such impressions. 
The boards supporting the bricks are then disposed in racks and the 
bricks dried for a few days, or until they may be turned on edge for 
further drying out. (-2) The compost may be used in a condition 
which is merely moist. It is compressed into the brick with some 
force, a mallet being often employed. The brick thus obtained is 



MUSHROOM SPAWN MAKING. 57 

sufficiently rigid to be immediately handled if necessary. By this 
method, unless the compost has been in excellent condition, the bricks 
are not so smooth as might be desired for commercial purposes. In 
Mime instances they have then been subjected to a repress process, 
an old repress brick machine being adapted for the purpose. In 
such cases the bricks are made thicker to begin with. The second 
method has been discontinued by some who at first employed it. 

Two methods are also employed in spawning: (1) The more com- 
mon method is to insert into the brick near both ends a piece of the 
virgin spawn obtained for the purpose. A cut is made with the 
knife, the spawn inserted, and a stroke of the knife effectively closes 
the surface. This must be done as soon as the brick can be readily 
handled. ( 2 ) The bricks are dried until merely moist throughout; 
then, on being piled, nocules of spawn are placed between successive 
bricks, a piece at each end. In either case the bricks are not piled 
for the growth id' the spawn until in good condition as to moisture 
content. This should be determined not by the surface, but by the 
interior of 1 1 1 » - brick. In the pile the surface will soon become moist. 
"When the first method is employed it is sometimes customary to 
spread between the layers of brick in the pile a little moist manure 
or sawdust. It has been determined, also, that the absolute mois- 
ture content of the brick should be about 40 per cent, which is the 
same as for the mushroom bed. Tests of the moisture content of 
bricks growing well have varied from 35 to 47\ per cent. 

Occasional examination should be made to determine the tempera- 
ture and the extent of growth. In order that the bricks may become 
thoroughly penetrated, more than a month will usually be required. 

The most favorable conditions for the growth of the spawn are 
practically the same as for mushroom growing. A fairly moist 
atmosphere, maintained, if necessary, by spraying, and a more or 
less uniform temperature (55° to (if) c F. ) are to be preferred. The 
size of the piles will depend upon the other conditions; but if there 
is any danger of considerable fermentative activity the bricks should 
be so disposed as to permit perfect ventilation between two or more 
adjacent rows. 

When the bricks are thoroughly " run *' they are dried under cover 
before being shipped or stored in bulk, since in a moist brick the 
spawn would continue to grow and would soon produce small mush- 
rooms or else would become moldy. Well-penetrated bricks of spawn 
are shown in Plate VII. figure '2. The areas of mycelial growth 
should lie evident to the eve. The growth should lie moldlike, how- 
ever, rather than composed of very large threads or fibers. 

The suggestion made in a previous publication that mushroom 
spawn should be sold by the brick (with a uniform standard of size) 
seems to have been adopted by American makers. The trade names 



. r )8 MUSHROOM GROWING AND SPAWN MAKING. 

suggested for the common types of Agaricus campestris in culture 
have also come into use. It is certain that these names, Alaska, 
Bohemia, and Columbia, designating respectively a white, a brown, 
and a more or less cream-gray form, do not include all forms in 
cultivation. Until a careful study has been made of varieties, how- 
ever, this nomenclature will enable spawn makers to keep in mind 
certain types, and will make it possible for growers to ask for a 
spawn yielding :• color demanded by their special markets. 

THE VITALITY OF MUSHROOM SPAWN. 

Many of the early experiments in mushroom growing undertaken 
by the writer were made in the hope of being able to ascertain the 
more frequent causes of failure and some of the chief difficulties 
encountered by American mushroom growers. The ordinary com- 
mercial spawn used by amateurs, that is, such as is obtainable upon 
the market during the winter months, was purchased wherever possi- 
ble. Samples of this spawn were placed under conditions which were 
supposed to he most • favorable for growth. Nevertheless, in the 
majority of cases there was no indication of the development of a 
new mycelium from the bricks of spawn thus obtained. From these 
results it was suspected that much of the spawn which reaches the 
amateur grower may be considerably injured, or even killed, by 
transportation or improper conditions of storage: for it must be sup- 
posed that most of this spawn is in good or at least fair condition 
when exported from Europe. 

Subsequently the writer was able to look into the matter of spawn 
making in Europe and France, and he was convinced that the diffi- 
culty of securing good spawn in England is not a very serious factor. 
The same is true with reference to the material which is obtained by 
both extensive and small growers in France. 

Special importations of some of the commercial English and 
French spawns were made, and this was packed, shipped, and stored 
under conditions as favorable as may ordinarily obtain. This spawn 
was imported during midwinter and stored until March or early 
April, when it was used in spawning some experimental beds. The 
conditions of the experiments were practically the same throughout, 
yet in not more than half the beds was there a favorable development 
of mushroom spawn, A distribution of the French spawn, both the 
commercial flake and the improved cake spawn, was made to several 
prominent American growers. Some of these growers experienced 
entire failure, while others reported that, after a slow beginning, beds 
spawned with this material made a good yield. The general conclu- 
sion, reenforced by observation and by the experience of practical 
growers, could only be that a large percentage of loss in mushroom 



VITALITY OF MUSHROOM SPAWN. 59 

growing is attributable to the injury suffered by the spawn after its 
preparation. This conclusion lias been further strengthened by the 
experience of the past three years. From Table VIII, beds Nos. 1. 
■2. 4. 5, and 30. it will be seen that, under conditions where fresh spawn 
has invariably made a good yield, the spawn which is more than a 
year old is. for the most part, seriously injured or killed. To be 
exact, in only one case was there any production of mushrooms by 
spawn which had been kept for a year or longer. It must be -aid that 
no attempt was made to keep these spawns under similar conditions or 
under the most favorable conditions. For the most part the spawn 
was stored in the dry laboratory room, in which the temperature was 
more or less variable, but never extreme. The old American spawn 
which was used in experimental bed No. 1. in Table VIII, was stored 
in a basement room where the average temperature was undoubtedly 
cooler than that of the Laboratory room. 

From experimental beds Nos. 1. ">. 4, and .">. in Table X. it is again 
-ecu that old spawn is unreliable. In this particular case the mate- 
rial was furnished by a prominent mushroom grower — an English 
spawn importer. This spawn had been stored in a dry house and 
was therefore subject to similar conditions. In Table VIII, beds 
Nos. 31, •">•_'. 35, and in Table IX. Nos. :',4, 41. and 45, there is further 
proof of the loss of vitality in the imported spawn ordinarily offered 
for sale in many of our cities. In these cases spawn was bought on 
the market just as offered for sale to the amateur buyer; "'best on 
hand " was asked for, but no stipulation was made that is should be 
of recent importation, and no guaranty was asked. The tests were 
not, therefore, to compare the very best English with the best Amer- 
ican spawn, but merely to secure an indication of some of the causes 
of failure by the purchase at random of English and French spawn 
on the market. Even in times past the extensive mushroom growers 
have either imported their spawn direct, or made sure that they 
were obtaining the best product that the market could furnish. 
Unfortunately, it has not been possible to compare, in any experi- 
ments thus far concluded, the best English with the best American 
spawn. 

The results seem also to indicate that brick spawn maintains its 
vitality longer than the flake material, and that brick spawn made 
of loose, light material is less retentive of vitality than that made 
after the formula commonly followed in England. This proves to 
be an unfortunate factor to be dealt with in the attempt to reduce 
by all means the weight of the brick. The reduction in weight 
would be most desirable, since freight upon this material adds con- 
siderably to the price of market spawn. To the poor keeping quali- 
ties of loose spawn is perhaps due the large number of failures with 
French flake spawn, and perhaps also some of the failures with the 



60 MUSHROOM GROWING AND SPAWN MAKING. 

newer form of French brick spawn. The latter is made in the form 
of very small, thin bricks, which are unquestionably more affected 
by weather conditions than the larger English bricks. 

These results have seemed to demand that special attention should 
be given to methods of spawn making in the United States in order 
that growers might be able to secure this product as fresh as pos- 
sible. Moreover, it was desirable, as previously indicated, to at- 
tempt work leading to the selection and improvement of varieties. 
The success of the work in spawn making has been almost all that 
could have been anticipated. By the pure-culture methods described, 
several firms are now making grades of brick spawn which have 
yielded remarkably well. This fact is now thoroughly recognized 
by a large number of the best growers throughout the country. 
Probably as many as 50,000 bricks were sold during 1904, and it is 
perhaps to be expected that several hundred thousand will be sold 
during the present year. 

It is to be regretted that it has not yet been possible to abandon 
the pure-culture process by means of which the virgin spawn is made 
while retaining the advantages of selection. Nevertheless, it should 
be remembered that the very difficulties of this process insure its use 
only by those who are able to give it their best attention and who will 
doubtless develop it to the fullest commercial extent. It has not been 
supposed by the writer that the work thus far accomplished will en- 
able all mushroom growers to manufacture their own spawn with 
comparative ease. In other phases of horticultural work it is not so 
much to individual growers as to progressive seedsmen that we look 
for the best seed of improved varieties. The same thing apparently 
must be anticipated in the development of the mushroom industry. 
The growing of selected spawn may, in general, become a specialized 
process. 

Nevertheless, it is believed that in time a method of spawn pro- 
duction from spores without pure-culture precautions will be devel- 
oped. The necessity of developing immediately, or placing on a 
practical basis, the pure-culture process has temporarily directed the 
experimental work along other lines. 

O 



Bui. 85, Bureau of Plant In 


dustry, U. S Dept of Agriculture. PLATE 11. 




# 






£l 


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v^, 




^ i 


i ~<iB 






idfi^^^^l 


H v if 


^■Trfl fifen 


^■■JBf ' j$fr 1 




K-^Hb, ^-^' 


^ k -^uJHAy 


■i ■''•'' 




a, ' " "^Bi^^^^ail^L. ' i^jSl.jM 1 




M 1 



Fig. 1.— a Fine Cluster of Agaricus Campestris, the Horticultural Variety 

Columbia. 




Fiq. 2.— Morels (Morchella esculenta), One of the Finest Edible Fungi. 



Bui. 85, Bureau of Plant Industiy, U. S. Dept. of Agriculture. 



Plate Ml. 




Fig. 1.— Agaricus Fabaceus, the Almond-flavored 
Mushroom. 




Fig. 2.— Agaricus Villaticus, a Promising Species, Fleshy and Prolific. 



1 



Bui. 85, Bureau of Plant Industry, U. S. Dept. of Agncu.ture. 



Plate IV. 




Fig. 1.— A Young Specimen of the Common Puffball 
(Calvatia craniiformis". 




Fig. 2.— The Oyster Mushroom i Pleurotus ostreatusi, Growing on Decayed 

Willow Log. 



Bui. 85, Buieau of Plant Industry, U. S. Dept of Agriculture. 



Plate V. 




Fig. 1.— A Mushroom House Provided with Gas-piping Framework 
for Shelf Beds. 




Fig. 2.— The Preparation of Compost. 



Bui. 85, Bureau of Piant Industry, U. S. Dept. of Agriculture- 



Plate VI. 




Fig. 1.— A Large Mushroom Establishment— a Common Form of Mushroom House. 




Fig. 2.— The Method of Making Pure Cultures, Showing the Apparatus and 

Materials. 



Bui 85, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate VII. 







Fig. 1.— Mushrooms Prepared for the American Market. 




Fig. 2.— Good i "Well-Run"' Mushroom Spawn. Brick Form. 



B Mr '08 



LIBRARY OF CONGRESS 



'#m, 






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